Amphipols from A to Z

Amphipols (APols) are short amphipathic polymers that can substitute for detergents to keep integral membrane proteins (MPs) water soluble. In this review, we discuss their structure and solution behavior; the way they associate with MPs; and the structure, dynamics, and solution properties of the resulting complexes. All MPs tested to date form water-soluble complexes with APols, and their biochemical stability is in general greatly improved compared with MPs in detergent solutions. The functionality and ligand-binding properties of APol-trapped MPs are reviewed, and the mechanisms by which APols stabilize MPs are discussed. Applications of APols include MP folding and cell-free synthesis, structural studies by NMR, electron microscopy and X-ray diffraction, APol-mediated immobilization of MPs onto solid supports, proteomics, delivery of MPs to preexisting membranes, and vaccine formulation.

Susceptibility of human and murine Chlamydia trachomatis serovars to granulocyte- and epithelium-derived antimicrobial peptides

Four antimicrobial peptides, protegrin-1, RTD-1, cryptdin-4, and indolicidin, were tested for their ability to inhibit the in vitro growth of Chlamydia trachomatis serovars E, L2, and mouse pneumonitis (MoPn). In general, protegrin-1 was found to have the strongest anti-chlamydial activity. Overall, of the three serovars tested, L2 was the most susceptible while MoPn was the most resistant to these peptides.

Immunization with the Chlamydia trachomatis mouse pneumonitis major outer membrane protein can elicit a protective immune response against a genital challenge

Infertility, ectopic pregnancy, and chronic abdominal pain are frequent complications of genital infections with Chlamydia trachomatis. In an attempt to produce a vaccine to protect against this pathogen we purified and refolded the C. trachomatis mouse pneumonitis (MoPn) major outer membrane protein (MOMP). This preparation, mixed with Freund's adjuvant using vortexing or sonication, was used to immunize BALB/c mice that were subsequently challenged in the upper genital tract. Vaginal cultures were taken on a weekly basis, and mice were mated 6 weeks after the challenge. Gels of the vortexed MOMP showed a predominant band with a molecular size of 62 kDa and weaker bands at 42 and 132 kDa, while the sonicated MOMP had a single band with a molecular size of 42 kDa. Following immunization with these two preparations, strong humoral and cell-mediated immune responses were detected in the mice inoculated with the vortexed MOMP. On the other hand, mice immunized with the sonicated MOMP had a strong humoral immune response but a relatively weak cell-mediated immune response, as determined by a T-cell lymphoproliferative assay and level of cytokine production by splenocytes. Vaginal cultures showed that the mice immunized with the vortexed MOMP were significantly protected, as determined by a decrease in the number of animals with positive cultures, the length of time the mice shed viable organisms, and the number of inclusion-forming units recovered per mouse. Animals immunized with the sonicated MOMP, on the other hand, showed a weaker level of protection based on the same three parameters. After mating, the number of fertile animals and number of embryos per mouse were significantly higher for the mice immunized with vortexed MOMP, but not for the mice immunized with sonicated MOMP, compared to those of the control groups. In conclusion, immunization with a purified and refolded preparation of the C. trachomatis MoPn MOMP confers a significant level of protection in mice against a genital challenge.

Susceptibility of mice to vaginal infection with Chlamydia trachomatis mouse pneumonitis is dependent on the age of the animal

Mice from three strains, BALB/c (H-2(d)), C3H (H-2(k)), and C57BL/6 (H-2(b)), ranging from 5 to 14 weeks of age, were inoculated intravaginally with different doses of the Chlamydia trachomatis mouse pneumonitis serovar. Vaginal swabs taken at weekly intervals showed that the percentage of animals with positive cultures and the number of inclusion-forming units recovered per mouse were higher in the younger animals. Furthermore, vaginal shedding lasted longer in the young mice than in the older mice. In addition, following mating higher rates of infertility and a decrease in the number of embryos were observed in the infected young mice. In conclusion, susceptibility to a chlamydial vaginal infection is dependent on the age of the mice, with the older animals being more resistant.

Immunogenic and protective ability of the two developmental forms of Chlamydiae in a mouse model of infertility

To compare the ability of elementary bodies (EB) and reticulate bodies (RB) of the Chlamydia trachomatis mouse pneumonitis (MoPn) biovar to induce a protective immune response, two groups of BALB/c mice were inoculated and boosted twice, with UV-inactivated EB or RB in Freund's adjuvant. Two weeks after the last immunization mice were challenged with C. trachomatis in the ovarian bursa. Vaginal cultures collected for 6 weeks after the intrabursal challenge showed that mice inoculated with EB were significantly protected, while mice inoculated with RB were not. Six weeks after the genital challenge mice were mated. Mice immunized with EB showed significant protection as demonstrated by the number of animals which were fertile and the number of embryos present in the uterine horns. In contrast, no significant protection against infertility was observed in the mice immunized with RB.

Intranasal immunization with Chlamydia trachomatis, serovar E, protects from a subsequent vaginal challenge with the homologous serovar

To vaccinate against a vaginal challenge with Chlamydia trachomatis, C3H/HeJ (H-2k) mice were immunized intranasally (i.n.) or intraperitoneally (i.p.) with 1 x 10(6) inclusion forming units (IFU) of C. trachomatis, serovar E and i.n. with 1 x 10(6) UV inactivated IFU of serovar E. Animals inoculated i.n. with mock infected HeLa 229 cells were used as controls. Upon a vaginal challenge with 5 x 10(3) IFU of serovar E, mice immunized i.n. with viable serovar E exhibited significant protection as judged by the number of mice infected compared to controls (p < 0.05). In contrast, mice immunized i.n. with serovar E that had been UV-inactivated, were not protected from a subsequent vaginal challenge with serovar E. Mice immunized i.p. with serovar E showed attenuation of the infection by 4 weeks after challenge compared to control mice as to the number of animals with positive vaginal cultures (p < 0.05). Of the immune parameters examined, the best correlation with protection was seen with Chlamydia specific IgG and IgA vaginal titers and lymphoproliferative responses to serovar E. In summary, mucosal immunization with viable serovar E partially protected mice against a subsequent vaginal challenge, thereby showing that it is possible to elicit a protective response to a human strain of C. trachomatis at a distant mucosal site in this animal model.

Immunization with a peptide corresponding to chlamydial heat shock protein 60 increases the humoral immune response in C3H mice to a peptide representing variable domain 4 of the major outer membrane protein of Chlamydia trachomatis

C3H (H-2(k)) mice are susceptible to a vaginal challenge with human strains of Chlamydia trachomatis and thus are a useful strain for testing potential Chlamydia vaccine candidates. However, C3H mice are fairly poor responders in terms of the level of antibody resulting from immunization with potential protective peptides representing variable domains (VDs) of the major outer membrane protein (MOMP). C57BL/6 (H-2(b)) mice, on the other hand, are moderately resistant to a vaginal challenge but are good responders to the chlamydial MOMP VDs. Peptides representing universal T-cell helper epitopes were employed to determine whether the antibody response to a peptide representing VD4 of the MOMP, which has been shown to contain neutralizing epitopes, could be enhanced in C3H and C57 mice. Universal T-cell helper peptides from tetanus toxin, the pre-S2 region of hepatitis B virus, and the mouse heat shock protein 60, as well as the corresponding segment of the Chlamydia heat shock protein 60 (hspct), were coadministered with the VD4 peptide. Peptides were coencapsulated in liposomes containing the adjuvant monophosphoryl lipid A and administered by using a combination of mucosal and intramuscular injection. The only T-cell helper peptide that improved the immune response as judged by antibody level, in vitro neutralization assays, and T-cell proliferation was hspct. The response in the C57BL/6 strain was not significantly enhanced with hspct over levels achieved with VD4 alone; however, in C3H mice the levels of serum antibody to C. trachomatis increased to that seen in C57 mice. However, the molecular specificity and immunoglobulin subclass distribution differed from those of the C57 response, and the neutralizing titers and T-cell proliferation responses were lower. In both strains of mice, titers of vaginal antibody to C. trachomatis were low. In summary, of the T-helper peptides used, only hspct significantly enhanced the immune response of C3H mice to the VD4 peptide, but it had only a modest effect on the immune response of C57 mice.

Chlamydia infections and heart disease linked through antigenic mimicry

Chlamydia infections are epidemiologically linked to human heart disease. A peptide from the murine heart muscle-specific alpha myosin heavy chain that has sequence homology to the 60-kilodalton cysteine-rich outer membrane proteins of Chlamydia pneumoniae, C. psittaci, and C. trachomatis was shown to induce autoimmune inflammatory heart disease in mice. Injection of the homologous Chlamydia peptides into mice also induced perivascular inflammation, fibrotic changes, and blood vessel occlusion in the heart, as well as triggering T and B cell reactivity to the homologous endogenous heart muscle-specific peptide. Chlamydia DNA functioned as an adjuvant in the triggering of peptide-induced inflammatory heart disease. Infection with C. trachomatis led to the production of autoantibodies to heart muscle-specific epitopes. Thus, Chlamydia-mediated heart disease is induced by antigenic mimicry of a heart muscle-specific protein.

Vaccination of mice with DNA plasmids coding for the Chlamydia trachomatis major outer membrane protein elicits an immune response but fails to protect against a genital challenge

A DNA plasmid encoding the gene of the major outer membrane protein (MOMP) of the Chlamydia trachomatis mouse pneumonitis (MoPn) serovar and three plasmids containing the variable domains (VD) of the MOMP were constructed. Female mice were inoculated with the plasmids and 60 days later were challenged in the genital tract with C. trachomatis. Six weeks after challenge female mice were caged with male mice and the course of the mating followed. Mice immunized with the MOMP plasmids mounted weak humoral and cell mediated immune responses. However, following the genital challenge no significant differences in vaginal shedding were observed between the groups immunized with the MOMP and control plasmids. In addition, the fertility rates were similar in the experimental and negative control groups. In conclusion, vaccination with DNA plasmids encoding the MOMP elicited a modest immune response but did not protect against infection or disease.

Characterization of a neutralizing monoclonal antibody directed at the lipopolysaccharide of Chlamydia pneumoniae

Identification of protective epitopes is one of the first steps in the development of a subunit vaccine. One approach to accomplishing this is to identify structures or epitopes by using monoclonal antibodies (MAb) that can attenuate infectivity in vitro and in vivo. To date attempts to use this approach with Chlamydia pneumoniae have failed. This report is the first description of a MAb directed to the lipopolysaccharide (LPS) of Chlamydia that neutralizes both in vitro and in vivo the infectivity of C. pneumoniae. MAb CP-33, an immunoglobulin G2b (IgG2b), was identified from a fusion using splenocytes from mice immunized with C. pneumoniae TW-183. By Western blot analysis, MAb CP-33 exhibited genus-specific reactivity in that it recognized the LPSs of C. pneumoniae, Chlamydia trachomatis, and Chlamydia psittaci. MAb CP-33 did not react with 15 genera of gram-negative and gram-positive bacteria and Candida albicans. By using isolated LPS of Re mutants of Escherichia coli, Salmonella enterica serovar Minnesota, and recombinants expressing the 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) transferase gene kdtA of C. trachomatis, MAb CP-33 was shown to require for binding the presence of the genus-specific trisaccharide epitope alphaKdo(2-->8)alphaKdo(2-->4)alphaKdo. By employing synthetic oligosaccharides and neoglycoconjugates in an enzyme immunoassay (EIA) and EIA inhibition, it was further shown that MAb CP-33 differed from the extensively investigated prototype chlamydial LPS MAb S25-23. Most likely, MAb CP-33 recognizes a conformational epitope in which the alphaKdo(2-->8)alphaKdo(2-->4)alphaKdo trisaccharide is an essential structural component. When tested in an in vitro neutralization assay, MAb CP-33 gave a 50% neutralization titer of 8 ng/ml against C. pneumoniae TW-183. However, this MAb did not neutralize other C. pneumoniae strains, C. trachomatis, or C. psittaci. C. pneumoniae TW-183 was treated with either MAb CP-33 or a control IgG and then used to inoculate mice by the respiratory route. Five days after inoculation, there was a difference between the mice inoculated with the control IgG-treated inoculum and those inoculated with the MAb CP-33-treated organisms as to the number of mice infected as well as the number of inclusion-forming units recovered from lung cultures (P < 0.05). In summary, a Chlamydia-specific LPS MAb was able to neutralize in vitro the infectivity of C. pneumoniae TW-183.

Factors influencing the induction of infertility in a mouse model of Chlamydia trachomatis ascending genital tract infection

In women, infections due to Chlamydia trachomatis frequently result in long-term sequelae including chronic abdominal pain, ectopic pregnancy and infertility. In an attempt to characterise the pathogenesis of the infection, female C3H (H-2k) mice were inoculated intravaginally with different doses of C. trachomatis and then mated with proven male breeder mice. The inoculated mice developed a broad spectrum of clinical manifestations ranging from infertility to asymptomatic shedding. The dose inducing infertility in 50% of the mice was c. 10(5) inclusion-forming units of C. trachomatis. In another group of mice sampled at intervals after intravaginal inoculation, C. trachomatis was recovered from the upper genital tract starting at 24 h after infection. A higher percentage of animals infected during the luteal phase of the oestrous cycle had positive cultures from the middle and upper genital tract than when mice were inoculated during the follicular phase. These results indicate that rapid therapeutic intervention is required to avoid the sequelae resulting from C. trachomatis genital infection, and suggest that hormonal factors play a role in the pathogenesis of the disease.

Role of nitric oxide in the inhibition of cytochrome P450 in the liver of mice infected with Chlamydia trachomatis

In this study, we attempted to determine the effect of a systemic infection with Chlamydia trachomatis on cytochrome P450(CYP)-dependent metabolism in mice. Furthermore, we wanted to assess if these effects were mediated through NO. BALB/c(H-2d) female mice were inoculated intraperitoneally with the C. trachomatis mouse pneumonitis (MoPn) biovar, and induction of NO synthase (NOS) was detected by measuring [NOx] levels and inducible NOS protein content in peritoneal macrophages by Western blotting. Recovery of C. trachomatis from liver, lung, and spleen peaked at 4 days postinfection. Following cotreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase, there was a significant increase in the intensity and the length of the infection. Six days after inoculation with C. trachomatis, CYP1A- and CYP2B-mediated metabolism in the liver of the mice was diminished up to 49% of control levels. However, when animals were treated with N(G)-nitro-L-arginine methyl ester at days 4 and 6 postinfection, the decrease in the metabolism of CYP1A and CYP2B was largely blocked. These results suggest that C. trachomatis infection can depress cytochrome P450 in a manner similar to other types of infections and that NO is likely to be a mediator of this depression. This finding may be of significance to patients taking drugs that are metabolized by phase I enzymes during infections with some bacteria such as C. trachomatis.

Immunization with an acellular vaccine consisting of the outer membrane complex of Chlamydia trachomatis induces protection against a genital challenge

The ability to induce protection against a genital challenge was studied in BALB/c female mice with three Chlamydia trachomatis mouse pneumonitis (MoPn) major outer membrane protein (MOMP) preparations as well as an acellular vaccine consisting of the chlamydial outer membrane complex (COMC). The MOMP preparations were extracted with three different types of detergents, sodium dodecyl sulfate (SDS), n-octyl-beta-D-glucopyranoside (OGP), and Zwittergent 3-14 (Z3-14). A positive immunization control consisted of mice inoculated intranasally with 10(4) C. trachomatis MoPn inclusion-forming units (IFU). Mice inoculated with ovalbumin served as a negative control. Furthermore, a sham-immunized, nonchallenged group was included as a fertility control. Two weeks after the last immunization, the mice were challenged in the left ovarian bursa with 10(5) C. trachomatis MoPn IFU. Vaginal swabs were collected for culture, vaginal and serum samples were assayed for chlamydial-specific antibodies, and splenocytes were collected to determine the lymphoproliferative response. At 42 days after the challenge, the mice were mated with proven male breeder mice. Animals that were considered to be pregnant (as determined by weight) were killed, and the embryos were counted. A significant humoral and cell-mediated immune response was observed in all the groups of mice inoculated with chlamydial antigens. Antibodies to variable domain (VD)1 of the MOMP were detected in serum samples from all the immunized groups. However, antibodies to VD3 and VD4 were detected only in the groups immunized with the Z3-14-MOMP and the COMC. Mice immunized with COMC developed significant immunoglobulin A chlamydia-specific antibodies in the vagina, while mice immunized with the detergent-extracted MOMPs had low antibody titers. Following the intrabursal challenge, a significant decrease in the intensity and duration of vaginal shedding was noted in the mice immunized with COMC and a moderate decrease was noted in the group immunized with OGP-MOMP. No protection against the infection was noted in the groups of animals immunized with SDS- and Z3-14-MOMP. Furthermore, of the mice immunized with the COMC preparation, only 25% (4 of 20) shed C. trachomatis, as determined by vaginal culture, while 83% (40 of 48) of the control mice inoculated with ovalbumin were culture positive (P < 0.05). In addition, after mating, the mice inoculated with COMC were found to have fertility rates comparable to those of the control sham-immunized, nonchallenged animals (70% [14 of 20] versus 81% [17 of 21], respectively [P > 0.05]), and there were no significant differences between the average number of embryos per mouse in the two groups (5.1 versus 5.9, respectively [P > 0.05]). In contrast, mice immunized with the purified MOMP preparations were not protected against infertility. In summary, a preparation of the COMC protected mice against infection and infertility, supporting the feasibility of the development of an acellular vaccine against C. trachomatis infections.

Effect of immunoglobulin G isotype on the infectivity of Chlamydia trachomatis in a mouse model of intravaginal infection

It has been previously shown with an in vitro neutralization system that monoclonal antibodies (MAbs) to the major outer membrane protein (MOMP) of Chlamydia trachomatis, depending on the isotype of the MAb and the host cell used, can either neutralize or enhance the infectivity of this organism. MAbs to variable domain 4 (VD 4) of MOMP have been described that neutralize the infectivity of C. trachomatis when tested in a system in which either the host cell does not have detectable Fc gammaRIII receptors or complement is added to block the interaction of the MAb with the receptor. However, if Fc gammaRIII receptors are available, immunoglobulin G2b (IgG2b) MAbs to the VD 4 are able to enhance the infectivity of this pathogen. Two MAbs that recognize the sequence TLNPTIA in VD 4 of the MOMP but differ in isotype, E4 (IgG2b) and E21 (IgG1), were used to test whether in vivo the isotype of the MAb modulates the outcome of a vaginal infection in a murine model. A third MAb, CP33 (IgG2b), that recognizes the chlamydial lipopolysaccharide but does not neutralize infectivity of C. trachomatis, was also tested. Elementary bodies (EBs) of C. trachomatis, serovar E (BOUR), were pretreated with the three MAbs and were used to inoculate the vaginas of C3H/HeJ mice which had been pretreated with progesterone. Subsequently mice were monitored over a 5-week period with vaginal cultures. In the groups that were inoculated with EBs pretreated with MAbs directed to VD 4 of MOMP, there was a significant decrease (P < 0.05) in the number of mice infected. Only 30% of the mice were infected in the MAb E4-treated group, and 10% were infected in the MAb E21 group. This was in contrast to the groups inoculated with EBs pretreated with MAb CP33 and control untreated EBs, which resulted in 100 and 79% of the mice infected, respectively. Therefore, in this setting in which EBs were introduced in vivo coated with MAb, there was no enhancement of infection by IgG2b MAbs; rather, the results paralled the in vitro neutralization results, in which cells lacking Fc gammaRIII receptors were employed. Mice were also given the MAbs, as well as purified IgG as a control, by intraperitoneal injection before and after intravaginal inoculation with C. trachomatis. Despite relatively high levels of MAbs in serum and detectable levels of MAbs in the vagina at the time of infection, there was only modest protection in animals receiving MAb E21, with 60% of the mice infected in contrast to 90% of the mice receiving MAb E4, MAb CP33, and IgG. However, by the second week of infection compared to controls, there was a significant increase (P < 0.05) in the amount of chlamydiae recovered from the vaginas of mice that had received the two IgG2b MAbs, E4 and CP33. In summary, the presence of IgG2b MAbs directed to surface components of C. trachomatis at certain times during the course of infection may play a role in enhancing the infectivity of this pathogen.

Monoclonal immunoglobulin A antibody to the major outer membrane protein of the Chlamydia trachomatis mouse pneumonitis biovar protects mice against a chlamydial genital challenge

In order to analyze the protective role that IgA may play in a chlamydial infection two IgA monoclonal antibodies (mAb), MoPn 4-2 and MoPn 13-2, were raised against the major outer membrane protein (MOMP) of the Chlamydia trachomatis mouse pneumonitis (MoPn) biovar. mAb MoPn 4-2 was found to be serovar specific while mAb MoPn 13-2 was species specific. mAb MoPn 4-2 recognized a surface exposed conformational epitope as shown by its ability to bind to native EBs and nonreduced MOMP while failing to bind to heat and trypsin treated EBs, to reduced MOMP and to synthetic MOMP peptides. In contrast, mAb MoPn 13-2 recognized a nonconformational epitope since it was able to bind treated EBs, to reduced MOMP and to the synthetic peptide MTTWNPTISGSGI located in variable domain 4 of the MOMP. Both mAbs agglutinated intact EBs and had in vitro neutralizing activity. However, mAb MoPn 4-2 had a 20-fold higher in vitro neutralizing ability when compared to mAb MoPn 13-2 (50% neutralization at 5 micrograms ml-1 vs 100 micrograms ml-1). In an in vitro in vivo infectivity assay, mAb MoPn 4-2 protected mice against infertility when C. trachomatis MoPn elementary bodies were preincubated with the mAb before inoculation. In addition, passive transfer of mAb MoPn 4-2 resulted in significant protection as measured by a decrease in the number of mice infected, and in the intensity and duration of vaginal shedding. These results support previous findings suggesting that IgA antibodies can play a role in protection against a chlamydial infection, and further encourage work to develop vaccination strategies that elicit mucosal immunity.

Reproducibility problems with the AMPLICOR PCR Chlamydia trachomatis test

In an attempt to use an expanded "gold standard" in an evaluation of an antigen detection test for Chlamydia trachomatis, the AMPLICOR (Roche Diagnostics Systems, Inc., Branchburg, N.J.) PCR Chlamydia trachomatis test and culture were used with 591 sets of cervical specimens. Of the 591 specimens assayed, 35 were retested due to either an equivocal result by the PCR (19 samples) or a discrepancy between the results of culture, PCR, and the antigen detection method. During the repeat testing of the samples with equivocal and discrepant results, all but one interpretation change was due to the PCR result. In addition, upon repeat testing the PCR assay value measured in optical density units varied widely for 13 of these specimens. These 13 specimens were then tested in triplicate by the manufacturer with primers to the chlamydia plasmid and in duplicate with primers to the major outer membrane protein. Only 3 of the 13 specimens gave the same interpretation with these five replicates. In summary, reproducibility problems with the AMPLICOR test should be considered before it is incorporated as part of routine testing or used as an expanded gold standard for chlamydia testing.

Detection of antibodies to Coccidioides immitis by enzyme immunoassay

Two hundred twenty-six specimens (160 serum samples, 66 cerebrospinal fluid samples) were tested with the Meridian Premier Coccidioides enzyme immunoassay (MPC-EIA), and the results were compared with those of conventional serologic tests detecting complement-fixing (CF) and tube precipitin (TP) antibodies. Of the 73 positive specimens by CF, 72 were positive by MPC-EIA (72 IgG positive, 48 IgM positive) and 1 was indeterminate. Of the 132 specimens negative by CF, 126 were negative by MPC-EIA, 3 were IgM positive only, and 3 were indeterminate. Of the three patients with specimens positive for IgM only, CF demonstrated seroconversion within a month in one. All 21 specimens that displayed anticomplementary activity by CF were confirmed negative by agar gel immunodiffusion for CF antibodies (IDCF) and TP antibodies (IDTP); 20 of these serum samples were also negative by MPC-EIA, and 1 was indeterminate. After exclusion of the 25 specimens with anticomplementary or indeterminate activity, results of MPC-EIA were in agreement with those of CF in 99% of specimens. With CF as reference, MPC-EIA had a specificity of 98%, sensitivity of 100%, and positive and negative predictive values of 96% and 100%, respectively. Correlation coefficient values from linear regressions of log-2 CF titer vs MPC-EIA IgG index values were calculated at .290 for serum samples and .931 for cerebrospinal fluid.

Intranasal immunization induces long-term protection in mice against a Chlamydia trachomatis genital challenge

In an attempt to confer long-term protective immunity, BALB/c female mice were immunized intranasally with 10(4) inclusion-forming units (IFU) of the Chlamydia trachomatis mouse pneumonitis biovar (MoPn). Animals were subsequently challenged in the ovarian bursa with 10(5) C. trachomatis MoPn IFU at 60, 120, or 180 days post-intranasal immunization. Two control groups were included in the study. One control was sham immunized and mock challenged, and another group was sham immunized and challenged with 10(5) C. trachomatis MoPn IFU. Vaginal cultures were collected at regular intervals following the intrabursal challenge. In comparison with the sham-immunized mice, the animals that were intranasally immunized with C. trachomatis had significant protection, as shown by a reduction in the number of animals that had positive vaginal cultures and by a decrease in the intensity and length of the shedding. Furthermore, histopathological characterization of the genital tract following challenge, in the three groups of mice, showed a minimal inflammatory infiltrate in the C. trachomatis-immunized animals, when compared with the sham-immunized control group. Subsequently, the three groups of female mice that were challenged at 60, 120 and 180 days postimmunization were mated at 6 weeks following the challenge. Overall, in the mice intranasally immunized with C. trachomatis the fertility rates and the number of embryos were similar to those in the sham-immunized and mock-challenged group. In contrast, there was a significant increase in infertility in the groups of mice that were sham immunized and C. trachomatis challenged. In conclusion, intranasal immunization with C. trachomatis induces long-term protection against a genital challenge as shown by a decrease in the infection and infertility rates when compared with sham-immunized animals. Thus, this model may help to characterize the parameters of the immune response that are important in maintaining long-term protection and may aid in identifying the antigenic determinants involved in eliciting protection.

Role of neutrophils in controlling early stages of a Chlamydia trachomatis infection

Inoculation of mice with the granulocyte-depleting monoclonal antibody RB6-8C5 showed that neutrophils are critical protective effector cells during a Chlamydia trachomatis infection. In addition, administration of monoclonal antibody 2E6 demonstrated that extravasation of neutrophils into the peritoneal cavity in response to inoculation with the C. trachomatis MoPn biovar is dependent on the surface beta-2 integrin molecule CD18.

The effect of orientation within a chimeric peptide on the immunogenicity of Chlamydia trachomatis epitopes

Peptides representing the Chlamydia trachomatis major outer membrane protein variable domains (VD) 1 and 4 of serovars C and E, respectively, have been shown to elicit a neutralizing antibody response in mice. To assess whether the position within a chimeric peptide influences the immunogenicity of the epitopes, two constructs, VD 1-4 and VD 4-1, were made in which the position of the VD relative to the amino and carboxy terminals were rotated. C57BL/10 mice were immunized with 100 micrograms of peptide in complete Freund's adjuvant (FA) on day 0, followed by an immunization with peptide (100 micrograms) in complete FA on day 14. By day 21 the immunodominant epitope in both chimeras as measured by ELISA was the one located at the carboxy terminus. A pepscan of the VD 1-4 antisera revealed a main peak in VD 4 which had been previously identified by neutralizing MAbs. The VD 4-1 antisera gave a peak in the VD 1 region which did not correspond to regions previously mapped with neutralizing MAbs. The VD 1-4 antisera but not the VD 4-1 antisera was able to neutralize in vitro serovar E. In summary, the position of these chlamydial epitopes within a chimeric peptide greatly influenced the resulting immune response.

Diagnostic difficulties caused by a nonclamped Schizophyllum commune isolate in a case of fungus ball of the lung

The presence of clamp connections on hyphae and the development of fruiting bodies in culture are primary characters which allow identification of the basidiomycete Schizophyllum commune in cases of human infection. The diagnostic problems presented by a nonclamped, nonfruiting isolate from a dense mass in the right upper lobe of the lung in a female with a past history of pulmonary tuberculosis and diabetes are described. Several features of the isolated fungus, including rapid growth rate and white, dense, cottony colonies, tolerance to the fungicide benomyl at a concentration of 10 micrograms/ml, and susceptibility to cycloheximide at 400 micrograms/ml, suggested that it might be a basidiomycete. Transmission electron microscopy showed the presence of a dolipore septum with perforate pore cap characteristic of fungi in the class Holobasidiomycetes. However, species identification remained elusive until compatibility tests with known single-basidiospore isolates confirmed the identification of the sterile lung isolate as S. commune. Sequence analysis of the 5' internal transcribed spacer region of ribosomal DNA further supported conspecificity.

Value of terminal subcultures for blood cultures monitored by BACTEC 9240

Blood cultures collected in BACTEC Plus Aerobic/F bottles and BACTEC Plus Anaerobic/F bottles were monitored for 5 days by BACTEC 9240 and subsequent terminal subcultures. Of the 13,471 bottles subcultured, 11.0% (1,477 of 13,471) were culture positive. Of these, 94.0% (1,388 of 1,477) were detected by BACTEC 9240; the additional 6.0% (89 of 1,477) were considered to be false negatives by BACTEC 9240 since they were detected by terminal subculture only. The false-negative bottles consisted of 17 BACTEC Plus Aerobic/F and 72 BACTEC Plus Anaerobic/F bottles, accounting for 2.2 (17 of 786) and 10.4% (72 of 691) of the total positive aerobic and anaerobic bottles, respectively. The positive blood culture bottles most frequently not detected by BACTEC 9240 grew Pseudomonas spp. (24), Staphylococcus spp. (21), and yeasts (24). Of the 86 blood cultures represented by the 89 false-negative bottles, 41 would not have been identified as positive since the other bottle in the blood culture set was either a false negative or a true negative. In general, terminal subcultures of false-negative BACTEC bottles had heavy growth, indicating that BACTEC Plus media were able to support the growth of microorganisms, but the BACTEC 9240 instrument was unable to detect this growth.

A new computer model for estimating the impact of vaccination protocols and its application to the study of Chlamydia trachomatis genital infections

We describe a new computer model for studying the impact of vaccination protocols on the prevalence of disease. This state transition model uses two parameters, the forward rate and the cure rate, that are derived from epidemiological data to compute the percentage of individuals infected in the population. The cure rate is the percentage of individuals that are cured within one time step (which in this study is one year) and the forward rate is used to calculate the number of new infections due to transmission. The forward rate and the cure rate are incorporated into an update function that has the property that if the vaccination efficacy is 0%, or no vaccination is applied, then the percentage of individuals infected stays constant. We present computer simulations of this model designed to assess the influence of two variables on the prevalence of Chlamydia trachomatis infection in a study population. More specifically, we determined the effect of vaccines with efficacies ranging from 50% to 100% and we analysed the impact on the population for vaccines efficacious for periods of 10, 20 and 40 years. The results of the computer simulation show that even the least efficacious vaccination programme rapidly decreases the prevalence of C. trachomatis infection in the population. On the other hand, a vaccine that is efficacious for a period of only 1 year had minimal impact on the prevalence of the disease in the total population.

Protection against infertility in a BALB/c mouse salpingitis model by intranasal immunization with the mouse pneumonitis biovar of Chlamydia trachomatis

Female BALB/c mice were immunized intranasally with the mouse pneumonitis biovar of Chlamydia trachomatis and subsequently challenged in the ovarian bursa (C. trachomatis immunized, C. trachomatis challenged). Two groups of mice served as controls. One group was sham immunized intranasally with mock-infected HeLa 229 cell extracts and was challenged in the ovarian bursa with C. trachomatis MoPn (sham immunized, C. trachomatis challenged). The second control group was sham immunized and not challenged (sham immunized, nonchallenged). Before challenge, the C. trachomatis-immunized, C. trachomatis-challenged animals mounted a significant humoral response as shown by high immunoglobulin G (IgG), IgM, and IgA levels and high levels of neutralizing antibodies in serum and moderate IgG and IgA titers in vaginal secretions. Reactivity by Western blot (immunoblot) to the lipopolysaccharide, 30-, 40- (major outer membrane protein), and 60-kDa cysteine-rich proteins and 75- and 100-kDa chlamydial components could be demonstrated. However, reactivity to the 60-kDa heat shock protein was only observed 22 days after challenge. In addition, this group of animals mounted a significant immune response to chlamydial antigens, as shown by a lymphocyte proliferation assay, compared with the sham-immunized nonchallenged mice. After intrabursal challenge, there was no C. trachomatis shedding from the vagina in the C. trachomatis-immunized, C. trachomatis-challenged animals, while 63% of the sham-immunized, C. trachomatis-challenged mice had a positive C. trachomatis culture. In addition, histological sections from the genital tract showed, at 2 weeks postchallenge, a marked acute inflammatory reaction in the sham-immunized, C. trachomatis-challenged animals while in the C. trachomatis-immunized, C. trachomatis-challenged mice there was minimal inflammatory reaction. When the animals were mated, only 12% of the mice from the sham-immunized, C. trachomatis-challenged mice were fertile. In contrast, 94 and 80% of the sham-immunized, nonchallenged and C. trachomatis-immunized, C. trachomatis-challenged mice, respectively, were fertile.

Comparison of the ProSpecT and Color Vue enzyme-linked immunoassays for the detection of Cryptosporidium in stool specimens

Two enzyme-linked immunosorbent assays, the ProSpecT (Al-exon, Sunnyvale, CA, USA) and the Color Vue (Seradyn, Indianapolis, IN, USA) were compared for their ability to detect Cryptosporidium in 236 formalin-fixed stool specimens using the Merifluor C/G (Meridian, Cincinnati, OH, USA) stain as the reference method. The initial sensitivities of the ProSpecT and the Color Vue were 96.0% and 76.0%, which upon repeat testing of all discrepancies remained at 96.0% for the ProSpecT and decreased to 72.0% for the Color Vue. There were 25 (11%) specimens positive by the reference method. Initially, there were five false positive specimens by the ProSpecT, only one of which remained positive on retesting. The specificity of the Color Vue was 100% for the initial and repeated results, whereas the ProspecT had an initial specificity of 97.6% that increased to 99.5% upon repeat testing. The enzyme-linked immunosorbent assays offered the advantages of objectivity, batch testing, and, in the case of the ProSpecT, an acceptable sensitivity.

Induction of infertility by the Chlamydia trachomatis mouse pneumonitis biovar in strains of mice that differ in their response to the 60 kDa heat shock protein

To determine the role that the host response to the chlamydial 60 kDa heat shock protein (hsp) plays in the pathogenesis of infertility, C3H/HeN (H-2k) and C57BL/6 (H-2b) mice were inoculated in the left ovarian bursa with 1 x 10(5) inclusion forming units of the Chlamydia trachomatis mouse pneumonitis (MoPn) biovar, and in the right ovarian bursa with mock-infected HeLa-229 cell extracts. Control mice were inoculated with mock-infected HeLa-229 cell extracts. These two strains of mice were chosen because the C3H mice mount a strong immune response to the 60 kDa hsp, whereas the C57BL/6 mice respond only weakly. Vaginal cultures obtained after inoculation were positive for 4 weeks in both strains of mice. Histological sections showed a marked acute inflammatory infiltrate that permeated all the layers of the oviduct and lasted for approximately 2 weeks in both strains. By the third week, mononuclear inflammatory cells were also observed and from 4 weeks after inoculation, hydrosalpinx formation was observed, particularly in the C3H mice. An inclusion immunofluorescence assay detected antibodies specific for chlamydia in the serum and the vaginal washes of the C3H and C57BL/6 mice. Western blot analysis of the serum samples showed an immune response to lipopolysaccharide, and the 30, 40 (major outer membrane protein) and 60 kDa cysteine-rich protein in both strains of mice. In addition, in the C3H mice a strong immune reaction was mounted against a 50 kDa component and the 60 kDa hsp. Six weeks after inoculation, the female mice were mated with male mice of proven fertility and the outcome of the pregnancies evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the humoral response elicited in mice by a chimeric peptide representing variable segments I and IV of the major outer membrane protein of Chlamydia trachomatis

A synthetic chimeric peptide representing the variable segments I (VS I) and IV of the major outer membrane protein (MOMP) of Chlamydia trachomatis, serovars C and E respectively, was studied to determine its ability to elicit a neutralizing humoral response in mice. Antibody responses varied to the peptide in the five inbred strains of mice, A/J(H-2a), DBA/1(H-2q), C57BL/10(H-2b), CBA/J(H-2k), Balb/c(H-2d), that were immunized. There was a spectrum of antibody responses which ranged from high ELISA and IFA titres by the C57BL/10 mice to little or no response by Balb/c mice. Antisera from C57BL/10 mice recognized all 15 serovars of C. trachomatis in a dot blot assay. A pepscan of the antisera from C57BL/10 mice showed strong reactivity to both neutralizing epitopes VAGLQNDPT in VS I of serovar C and the species-conserved peptide, TLNPTIA, in the VS IV. This antiserum neutralized, in vitro, the infectivity of serovars representing the B complex (B, D and E), C complex (C and J), B-related (F) and C-related (L3) complexes. In an attempt to elicit a stronger response to the peptide in the weakly reactive Balb/c and the DBA/1 strains, the peptide was conjugated to the carrier, keyhole limpet haemocyanin (KLH). All mice immunized with the KLH-peptide produced high-titred antisera that recognized neutralizing epitopes in VS I and VS IV and strongly neutralized the infectivity of both serovars C and E.

Intravaginal inoculation of mice with the Chlamydia trachomatis mouse pneumonitis biovar results in infertility

In an attempt to establish a model of chlamydial ascending salpingitis and infertility, three inbred strains of mice, C3H/HeN (H-2k), C57BL/6N (H-2b), and BALB/cAnN (H-2d), were inoculated intravaginally with 3 x 10(7) inclusion-forming units of the Chlamydia trachomatis mouse pneumonitis biovar. Mice mated 6 weeks following inoculation were found to have a significant decrease in fertility rate compared with the control groups, as shown by a reduction in the number of pregnant mice and a decrease in the number of embryos.

Phylogenetic analysis of the outer-membrane-protein genes of Chlamydiae, and its implication for vaccine development

Examination of 18 complete and 6 partial sequences of the major outer-membrane protein from 24 chlamydiae isolates was used to reconstruct their evolutionary relationships. From this analysis, assuming that the clades with 100% bootstrap support are correct, come the following conclusions: (1) The tree of these sequences is not congruent with the phylogeny of the hosts, and thus host switching would seem to have occurred, thereby limiting the extent to which there has been coevolution of parasite and host. (2) The tree is also noncongruent with clustering by type of cell infected, thereby limiting the extent to which there has been coevolution of parasite and the cell type that it infects. (3) The tree is also noncongruent with clustering by the organ infected (eyes or genitalia), thereby limiting the extent to which there has been coevolution of parasite and the organ that it infects. (4) The tree is also noncongruent with genital strains arising from lymphogranuloma venereum strains. (5) The tree is also noncongruent with the geographic site at which the isolates were obtained, thereby limiting the extent of divergence explained by geographic separation. (6) There are estimated to be 185 amino acid positions that are invariable (as opposed to unvaried) in the major outer-membrane protein. There are 10 unvaried positions in the variable domains, of which 9 appear to be invariable, giving some reason to hope that development of a vaccine might be possible. (7) The rate of change of this protein is too small to see increased divergence over the time span of isolation of these genes, giving hope to any vaccine having longevity. Bootstrapping supports those portions of the tree on which the first five conclusions above depend. The picture that these results provide is more one of pathogen versatility than one of coevolutionary constraints. In addition, we examined 10 60-KDa, outer-membrane protein-2 genes, all but one of which were from these same strains. The tree was not, among the trachomatis strains, congruent with the major-outer-membrane protein tree, suggesting that gene exchange could be occurring among strains. Moreover, there is an apparent slowdown in divergence in this gene, among the trachomatis strains.

Mapping of a surface-exposed B-cell epitope to the variable sequent 3 of the major outer-membrane protein of Chlamydia trachomatis

A B-cell epitope, AEFPLDIT, was located to the variable sequent 3 of the major outer-membrane protein (MOMP) using the monoclonal antibody L3-1, raised to the Chlamydia trachomatis serovar L3 MOMP. By Western blot and inclusion immunofluorescence assay the monoclonal antibody recognized all the C complex and C-related complex serovars of C. trachomatis, except serovar C. Dot-blot and ELISA data using native elementary bodies indicated that the epitope was surface exposed. The monoclonal antibody, at concentrations of 10 and 100 micrograms per 10(7) chlamydial inclusion-forming units, was able to neutralize the infectivity of chlamydia in an in vivo assay but did not neutralize chlamydia in vitro or in a mouse toxicity assay. A peptide corresponding to the variable sequent 3 has previously been shown to also elicit a T-cell response; thus, careful consideration should be given to inclusion of this region of the major outer-membrane protein in a subunit vaccine.

Characterization of a neutralizing monoclonal antibody directed at variable domain I of the major outer membrane protein of Chlamydia trachomatis C-complex serovars

A monoclonal antibody (MAb), C10, that neutralized in vitro the infectivity of serovars C, I, J, and L3 (members of the C and C-related complexes) of Chlamydia trachomatis was identified. Of the 15 major serovars and the mouse pneumonitis strain of C. trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae, which were used as nontreated and heat-treated (56 degrees C, 30 min) antigens in a dot blot assay, only serovars C, I, J, and L3 were recognized with both the native and treated antigens. Western blot (immunoblot) results showed that MAb C10 recognized the major outer membrane protein of these four serovars. Overlapping hexameric peptides corresponding to variable domains (VDs) I, II, III, and IV of the major outer membrane protein of C. trachomatis serovar C were synthesized, and peptide screening showed that MAb C10 mapped to the VD I amino acid sequence VAGLQNDPT. Results of an in vitro neutralization assay correlated with those of the indirect immunofluorescence assay, Western blot, and dot blot assay in that only serovars C, I, J, and L3 were neutralized by MAb C10. In vitro competitive neutralization experiments, using a peptide representing VD I of serovar C to compete with C. trachomatis serovar C for MAb C10 binding, revealed that both serological and neutralizing activities of MAb C10 were inhibited by the VD I peptide. In an in vivo toxicity/infectivity assay using serovar L3 pretreated with MAb C10, there was 100% survival of mice infected with a lethal dose at 48 h. In contrast, the control group, consisting of mice injected with the same dose of L3 pretreated with a MAb that does not recognize L3, had no survivors during a 48-h observation period. In summary, since the surface-exposed contiguous epitope recognized by MAb C10 binds neutralizing antibodies that are subspecies specific for the C and C-related complexes, it should be considered for inclusion in the development of a chlamydial vaccine.

Comparison of different methods and cell lines for isolating measles virus

Infectivity titers were determined for seven strains of measles virus by using various methods and cell lines. The use of B95-8 cells in a shell vial assay resulted in the highest infectivity titers. Our data suggest that B95-8 is the cell line of choice for the isolation of measles virus.

Effects of antibody isotype and host cell type on in vitro neutralization of Chlamydia trachomatis

Monoclonal antibodies (MAbs) E-4, E-21, and DIII A3, which recognize the same or similar overlapping peptides in the variable domain IV of the major outer membrane protein of Chlamydia trachomatis but differ in isotype, were used in a complement-independent (CI) in vitro neutralization assay. These MAbs had previously been shown to neutralize chlamydial infectivity in HeLa 229 cells in a complement-dependent assay. In this report, all three MAbs neutralized chlamydial infectivity in HaK cells in a CI assay. However, when HeLa cells were used as the host cell, MAb E-4 (immunoglobulin G2b [IgG2b]) and MAb DIII A3 (IgG2b) failed to neutralize infectivity, while MAb E-21 (IgG1) neutralized chlamydial infectivity. These findings are consistent with the proposal that because of the presence of Fc gamma RIII receptors, HeLa cells facilitate infectivity and thus block neutralization through the uptake of an IgG2b-chlamydia complex. Since Fc gamma RIII receptors do not bind or bind poorly to IgG1, neutralization of C. trachomatis by MAb E-21 in HeLa cells is also corroborative evidence for the role of Fc gamma RIII receptors in this interaction. A fivefold enhancement of infectivity was seen when 10 and 1 micrograms of MAb E-4 per ml were tested in a CI assay with HeLa cells. In performing CI neutralization synergy studies in HeLa cells with MAbs E-4 and E-21, antagonism between MAbs E-4 and E-21 was observed at MAb E-4 concentrations of 10 and 1 micrograms/ml for all concentrations of MAb E-21 tested (10 to 0.1 micrograms/ml). When HaK cells were used in the same studies, no antagonism between the MAbs was found. In addition, when HeLa cells were used in a CI assay, polyclonal serum raised to a peptide representing variable domain IV of the major outer membrane protein inhibited the neutralizing ability of MAb E-21. The blocking of neutralization and the enhancement of infectivity by chlamydia-specific antibodies seen in this investigation with HeLa cells may have important clinical implications for developing preventive strategies for chlamydial infections.

Analysis of the immune response in mice following intrauterine infection with the Chlamydia trachomatis mouse pneumonitis biovar

A Swiss Webster white mouse model of salpingitis was used to characterize the immune response following an intrauterine infection with the Chlamydia trachomatis mouse pneumonitis biovar. Western blot (immunoblot) analyses of the serum samples showed that the immunodominant bands corresponded to molecular masses of 72, 60, 42, and 28 kDa and to the lipopolysaccharide. Antibodies to the 60-kDa heat shock protein and to the 60-kDa cysteine-rich protein were detected at 2 and 3 weeks postinfection, respectively. Neutralization was observed in an in vitro assay with serum samples as early as the 3rd day postinfection and remained high for the 7 weeks of observation. The mice were mated in the 7th week following infection. Of the infected experimental mice, 71.4% were found to be either unilaterally or bilaterally infertile, whereas only 27.4% of the noninfected control mice were found to be infertile.

Disseminated atypical blastomycosis in two patients with AIDS

Two men with AIDS developed fungal infections and subsequently died as a result of dissemination of the fungal infection. Findings obtained by histologic examination, serological studies, and cultures suggested that the infections were caused by Blastomyces dermatitidis. Tissue sections showed polymorphic yeast-like cells 5-20 microns in diameter (some with broad and others with narrow single- or multiple-based buds), small yeasts, and hyphal elements. The exoantigen K positivity and exoantigen A negativity of one of the isolates indicated that the fungus was more like an African than a North American serotype.

Identification of Mycobacterium tuberculosis and Mycobacterium avium-M. intracellulare directly from primary BACTEC cultures by using acridinium-ester-labeled DNA probes

Identification of members of the Mycobacterium tuberculosis complex and the M. avium-M. intracellulare complex (MAC) directly from primary BACTEC cultures was evaluated by using acridinium-ester-labeled DNA probes (AccuProbe; GenProbe, Inc., San Diego, Calif.). In preliminary experiments, blood present in samples was found to interfere with the assay because of nonspecific chemiluminescence, which was measured in relative light units (RLUs). There was a direct relationship between the age of the culture and the number of nonspecific RLUs. A protocol using 1% sodium dodecyl sulfate-5 mM EDTA to treat BACTEC broth cultures which, with specimens containing blood, gave on the average a ninefold reduction in nonspecific chemiluminescence was developed. By using this treatment protocol, 120 specimens were tested directly from BACTEC broth cultures with an AccuProbe for the M. tuberculosis complex and/or the MAC. In order to establish the background of the specimen, the patient sample was assayed without probe. The criteria for the inclusion of BACTEC cultures in the evaluation were a growth index of greater than or equal to 100 and a positive smear for acid-fast bacilli directly from the BACTEC broth. For the 120 cultures tested, if a hybridization result of greater than or equal to 30,000 RLUs was considered positive, the sensitivities for detecting the M. tuberculosis complex and the MAC were 47 and 90%, respectively, with a specificity of 100% for both. However, if a ratio of the RLUs obtained with the MAC or the M. tuberculosis complex probe to those obtained with the specimen background of >/= 20 was considered positive, this gave 77% sensitivity and 100% specificity for BACTEC cultures containing M. tuberculosis complex isolates and 96% sensitivity and 100% specificity for those growing MAC isolates.

Characterization of the humoral response induced by a peptide corresponding to variable domain IV of the major outer membrane protein of Chlamydia trachomatis serovar E

A 30-amino-acid peptide corresponding to variable domain IV (VD IV) of the major outer membrane protein of Chlamydia trachomatis serovar E was conjugated to keyhole limpet hemocyanin (KLH) and used to immunize mice. The resulting antisera (anti-KLH-VD IV sera) recognized all 15 serovars of C. trachomatis when assayed by indirect immunofluorescence and Western blotting. Probing of overlapping hexameric peptides representing VD IV with mouse anti-KLH-VD IV sera revealed that two main regions of the peptide were recognized by the antisera, the N terminus of the peptide, which contains B-complex-specific epitopes, and the middle region of the peptide, which contains a species-conserved domain. When used in an in vitro neutralization assay, these antisera were able to neutralize mainly serovars in the B complex. These data provide evidence that a linear peptide corresponding to VD IV can induce in vitro protection from C. trachomatis infectivity that is subspecies specific.

Comparison of commercially available media for detection and isolation of Ureaplasma urealyticum and Mycoplasma hominis

The Mycotrim Triphasic flask system (Irvine Scientific, Irvine, Calif.) was compared with a system composed of Mycotrim GU broth (Irvine Scientific) and A7 or A8 agar (Remel, Lenexa, Kans.) for the ability to detect Ureaplasma urealyticum and Mycoplasma hominis from 129 genital specimens. Of the 64 specimens positive for U. urealyticum, 25, 98, and 100% were detected on Mycotrim Triphasic agar and A7 and A8 agars, respectively. All 18 specimens that grew M. hominis were detected by A7 and A8 agars, and 94% grew on Mycotrim Triphasic agar. Mycotrim GU broth detected all of the positive specimens, and Mycotrim Triphasic broth detected all but one. Mycotrim GU broth inoculated simultaneously with either A7 or A8 agar was found to be more sensitive and cost-effective than the Mycotrim Triphasic flask system.

Detection of bacteriuria and pyuria by URISCREEN a rapid enzymatic screening test

A multicenter study was performed to evaluate the ability of the URISCREEN (Analytab Products, Plainview, N.Y.), a 2-min catalase tube test, to detect bacteriuria and pyuria. This test was compared with the Chemstrip LN (BioDynamics, Division of Boehringer Mannheim Diagnostics, Indianapolis, Ind.), a 2-min enzyme dipstick test; a semiquantitative plate culture method was used as the reference test for bacteriuria, and the Gram stain or a quantitative chamber count method was used as the reference test for pyuria. Each test was evaluated for its ability to detect probable pathogens at greater than or equal to 10(2) CFU/ml and/or greater than or equal to 1 leukocyte per oil immersion field, as determined by the Gram stain method, or greater than 10 leukocytes per microliter, as determined by the quantitative count method. A total of 1,500 urine specimens were included in this evaluation. There were 298 specimens with greater than or equal 10(2) CFU/ml and 451 specimens with pyuria. Of the 298 specimens with probable pathogens isolated at various colony counts, 219 specimens had colony counts of greater than or equal to 10(5) CFU/ml, 51 specimens had between 10(4) and 10(5) CFU/ml, and 28 specimens had between 10(2) and less than 10(4) CFU/ml. Both the URISCREEN and the Chemstrip LN detected 93% (204 of 219) of the specimens with probable pathogens at greater than or equal to 10(5) CFU/ml. For the specimens with probable pathogens at greater than or equal to 10(2) CFU/ml, the sensitivities of the URISCREEN and the Chemstrip LN were 86% (256 of 298) and 81% (241 of 298), respectively. Of the 451 specimens with pyuria, the URISCREEN detected 88% (398 of 451) and Chemstrip LN detected 78% (350 if 451). There were 204 specimens with both greater than or equal to 10(2) CFU/ml and pyuria; the sensitivities of both methods were 95% (193 of 204) for these specimens. Overall, there were 545 specimens with probable pathogens at greater than or equal to 10(2) CFU/ml and/or pyuria. The URISCREEN detected 85% (461 of 545), and the Chemstrip LN detected 73% (398 of 545). A majority (76%) of the false-negative results obtained with either method were for specimens without leukocytes in the urine. There were 955 specimens with no probable pathogens or leukocytes. Of these, 28% (270 of 955) were found positive by the URISCREEN and 13% (122 of 955) were found positive by the Chemstrip LN. A majority of the false-positive results were probably due, in part, to the detection of enzymes present in both bacterial and somatic cells by each of the test systems. Overall, the URISCREEN is rapid, manual, easy-to-perform enzymatic test that yields findings similar to those yielded by the Chemstrip LN for specimens with both greater than or equal to 10(2) CFU/ml and pyuria or for specimens with greater than or equal to 10(5) CFU/ml and with or without pyuria. However, when the data were analyzed for either probable pathogens at less 10(5) CFU/ml or pyuria, the sensitivity of the URISCREEN was higher (P less than 0.05).

Functional and structural mapping of Chlamydia trachomatis species-specific major outer membrane protein epitopes by use of neutralizing monoclonal antibodies

Three monoclonal antibodies (MAbs), E4, L1-4, and L1-24, to the major outer membrane protein (MOMP) of Chlamydia trachomatis were identified that neutralized in vitro the infectivity of members of the B- and C-related complex as well as the mouse pneumonitis strain. MAbs L1-4, L1-24, and E4 gave a strong signal in an indirect immunofluorescence assay and/or Western immunoblot with all serovars of the lymphogranuloma venereum and trachoma biovars and a weak signal with the mouse biovar. In addition, C. psittaci and C. pneumoniae were also weakly recognized by MAbs L1-4 and L1-24. As determined by the technique of pneumoniae were also weakly recognized by MAbs L1-4 and L1-24. As determined by by the technique of overlapping peptides, all three MAbs showed reactivity to variable domain (VD) IV of MOMP. While all three MAbs had different recognition patterns, all strongly bound to the peptides TLNPTI and LNPTIA within the species-conserved region of VD IV. MAb E4 also recognized the peptide SATAIF in the subspecies region of VD IV. Peptides corresponding to VD IV of MOMP were synthesized and used in competitive inhibition experiments to determine the functional location of the epitope recognized by these three MAbs. Both the serological and neutralizing activities of MAb E4 were inhibited by the peptides ATAIFDTTTLNPTIAG and FDTTTLNPTIAG; however, none of the peptides made to the VD IV region blocked the neutralizing activity of MAbs L1-4 and L1-24. Therefore, the neutralizable domain of the epitope recognized by MAb E4 is contiguous and may be an important candidate for inclusion in a subunit vaccine.

Sequence of the gene encoding the major outer membrane protein of the mouse pneumonitis biovar of Chlamydia trachomatis

The gene encoding the major outer membrane protein of the Chlamydia trachomatis mouse pneumonitis biovar was sequenced and the amino acid sequence deduced. The primary structure of this protein is similar to that of the lymphogranuloma venereum and trachoma biovars in that it consists of four variable domains interspersed with five constant domains. This protein may be an ideal candidate for a vaccine in chlamydia-infected mouse experimental models.

Evaluation of the rapid CLEARVIEW Chlamydia test for direct detection of chlamydiae from cervical specimens

The CLEARVIEW Chlamydia test (Unipath, Mountain View, Calif.), a 30-min immunoassay, was compared to a standard tissue culture technique for the direct detection of chlamydiae from 677 cervical specimens obtained from 667 patients. For data analysis, 15 specimens were eliminated because of toxicity in the culture and 14 were eliminated because of failure of the extracted specimen to migrate in the CLEARVIEW test, one of the latter group being culture positive. Of the remaining 648 specimens, 40 were culture positive, of which 38 were detected by the CLEARVIEW test, and 12 specimens were positive only by the CLEARVIEW test. Therefore, the CLEARVIEW in comparison with culture was easier to perform, more rapid, and in this low prevalence (6.2%) population had a 95.0% sensitivity, 98.0% specificity, and 76.0% positive and 99.7% negative predictive values.

Nucleotide sequence of DNA encoding the major outer membrane protein of Chlamydia trachomatis serovar L3

DNA encoding the major outer membrane protein of Chlamydia trachomatis serovar L3 was sequenced following amplification by the polymerase chain reaction. A comparison with the deduced amino acid (aa) sequence of the C. trachomatis serovar L2 showed that the L3 had three extra aa and 55 aa substitutions.

Comparison of monoclonal antibody and calcofluor white stains for the detection of Pneumocystis carinii from respiratory specimens

Three monoclonal antibody staining kits, from Genetic Systems, Disease Detection International, and Meridian Diagnostics, were compared with calcofluor white for the direct detection of Pneumocystis carinii in respiratory specimens. Of the 150 specimens tested, 23 were found positive for P. carinii by any of the four stains; 13 were bronchoalveolar lavage, 7 were induced sputum and 3 were expectorated sputum specimens. All stains detected the positive bronchoalveolar lavage specimens, the Genetic Systems stain detected six induced sputum specimens, and the other stains each detected four induced sputum specimens. The monoclonal antibody stains detected all three expectorated specimens, while the calcofluor stain detected only one. Overall, the sensitivities of the stains were 96% for Genetic Systems, 87% for both Disease Detection International and Meridian Diagnostics, and 78% for calcofluor.

Differences in susceptibilities of the lymphogranuloma venereum and trachoma biovars of Chlamydia trachomatis to neutralization by immune sera

Sera from seven patients from whom a C. trachomatis serovar L2 strain was isolated were tested in vitro for their ability to neutralize the infectivity of this organism. In one patient an inguinal lymph node was culture positive, whereas the remaining six patients had positive rectal biopsies. Sera from four of the patients, including the patient with the lymph node isolate, failed to neutralize serovar L2(434). In addition, the homologous strain recovered from the inguinal lymph node was available and was resistant to neutralization by the homologous sera. However, the same sera effectively neutralized a trachoma serovar, E(Bour). All four sera had inclusion immunofluorescent-antibody titers to C. trachomatis serovar L2 of 2,048 to 16,384 and microimmunofluorescent-antibody titers to the lymphogranuloma venereum biovar were equal or higher in all cases than to the 12 serovars of the trachoma biovar. The three remaining sera, while neutralizing the infectivity of the L2 strains tested, neutralized serovar E to a greater extent. These sera had the same inclusion immunofluorescent antibody titers as the sera that failed to neutralize serovar L2. To see whether this difference in the sensitivity of the biovars toward neutralization could be characterized, sera were obtained from mice immunized with different doses of both serovars L2 and E. Sera obtained from mice immunized with serovar E were able to effectively neutralize the homologous strain. In contrast, neutralization of the immunizing strain, L2(UCI-20), was not seen with sera obtained on days 7, 14, and 21 after immunization from animals receiving 8 x 10(5) and 8 x 10(4) inclusion-forming units of L2(UCI-20); however, these same sera neutralized serovar E. However, with a higher immunizing dose of L2 (10(7) IFUs), both E and L2 were neutralized with sera obtained 7 and 14 days after immunization. Therefore, the relative resistance to neutralization by serovar L2 compared with that of serovar E in the mouse model was inoculum dependent.