Therapeutic effect of DNA immunization of genetically susceptible mice infected with virulent Mycoplasma pulmonis

Genetically susceptible BALB/c mice were immunized i.m. with DNA for one or two Mycoplasma pulmonis Ags (A7-1, A8-1) beginning either 1 wk before (vaccination) or 1 wk after (treatment) intranasal infection with 5 x 10(4) CFU virulent M. pulmonis organisms. Immunization of mice by this method induced both humoral and cellular immunity to M. pulmonis, largely prevented infection (vaccination), and cleared an ongoing pneumonia over time (treatment). Only one Ag gene was required. Thus, DNA immunization is a potential treatment for infections and may be useful in instances when drug therapy may not be available or effective.

Therapeutic effect of DNA immunization of genetically susceptible mice infected with virulent Mycoplasma pulmonis

Genetically susceptible BALB/c mice were immunized i.m. with DNA for one or two Mycoplasma pulmonis Ags (A7-1, A8-1) beginning either 1 wk before (vaccination) or 1 wk after (treatment) intranasal infection with 5 x 10(4) CFU virulent M. pulmonis organisms. Immunization of mice by this method induced both humoral and cellular immunity to M. pulmonis, largely prevented infection (vaccination), and cleared an ongoing pneumonia over time (treatment). Only one Ag gene was required. Thus, DNA immunization is a potential treatment for infections and may be useful in instances when drug therapy may not be available or effective.

Expression of avrPphB, an avirulence gene from Pseudomonas syringae pv. phaseolicola, and the delivery of signals causing the hypersensitive reaction in bean

Protein production encoded by the avirulence gene avrPphB from Pseudomonas syringae pv. phaseolicola was examined. Incorporation of [35S]-labeled methionine into the AvrPphB protein indicated processing of the full-length peptide in Escherichia coli to give a major 28-kDa product. The 28-kDa native peptide was isolated from E. coli following over-expression of avrPphB and found not to elicit the hypersensitive response (HR) after infiltration into bean leaves. Antiserum raised to the 28-kDa peptide allowed expression of avrPphB and processing of AvrPphB protein to be examined in P. syringae pv. phaseolicola; immunoreactive peptides of both 35 and 28-kDa were detected in races 3 and 4 (which contain avrPphB) only after induction in minimal medium + 10 mM sucrose. Antiserum raised to a synthetic peptide, derived from the sequence of the 62 amino acids found to be cleaved from the full-length AvrPphB protein, revealed the accumulation of peptides corresponding to the smaller cleavage products, in both E. coli and P. syringae pv. phaseolicola. Biochemical localization experiments showed that all AvrPphB peptides were cytoplasmic in P. syringae pv. phaseolicola. No AvrPphB peptides were produced in a hrpL mutant unless expression of the gene was directed by a strong vector promoter; induction kinetics similar to wild type were observed in a hrpY- strain, although it also failed to cause a confluent HR. Growth of P. syringae pv. phaseolicola under inducing conditions removed the requirement for rifampicin-sensitive mRNA synthesis by bacteria to allow HR development (the induction time) in bean and lettuce leaves. Constitutive expression of hrpL reduced but did not remove the induction time. Expression of the hrp gene cluster of P. syringae pv. phaseolicola from plasmid pPPY430 in E. coli enabled phenotypic expression of avrPphE (also carried by pPPY430) and avrPphB (if over-expressed from pPPY3031). Despite constitutive expression of the hrp and avr genes in E. coli, a protein synthesis dependent induction time was still required for development of the HR in bean genotypes with matching resistance genes. The significance of processing for the function of AvrPphB peptides and the delivery of elicitors of the HR are discussed.

Murine marrow coexpressing H2-Dsp2 and H2-Db on host natural killer cell rejection

BACKGROUND

Class I molecules may inhibit or activate natural killer (NK) cells. H2-Dd, -Ld, or -Dsp2 (the latter derived from spretus mice) on bone marrow cells (BMC) are recognized and rejected by NK1.1+ NK cells. BMC of intra-H2 recombinants between H2sp2 and H2b were analyzed. The 9347 and R40 KbIbBat2b/Tnf(sp2)Dsp2 BMC were rejected by B6 hosts. However, B6 hosts reject and accept KbDsp2Db R40 x B6 and 9347 x B6 BMC, respectively. Thus, Db and/or H2-Bat2/Tnf interval genes may regulate the immunogenicity of H2-Dsp2+ BMC.

METHODS

R40 or 9347 mice were crossed with DBA.Db (H2d, Db) transgenic mice to produce F1 and F2 progeny. DNA synthesis (proliferation) in host spleens was the measure of marrow graft success. Results. (1) BMC of H2(9347 or R40)+ H2d-Db+ (but not Db-) F2 progeny grew in B6 hosts. (2) BMC of H2(9347 or R40) x DBA.Db F1 Kb/dDsp2/dDb progeny were rejected by B6, but not by B6D2F1 (H2b/d) or D8 (H2b, Dd) hosts. (3) NK cells were the effectors.

CONCLUSIONS

Db can reduce the immunogenicity of Dsp2+ BMC (F2 data), but not of Dd+ BMC (F1 data). Growth of F2 H2(R40) Db+, but not F1 R40 x B6, BMC grafts in B6 hosts could be based on gene(s) differences in the H2-Bat2/Tnf region. Alternatively, non-H2 genes of DBA/2 might be involved. The genes would provide peptides for Db heavy chains to form "protective motifs" that send negative signals to host NK cells.

Role of murine NK cells and their receptors in hybrid resistance

Hybrid resistance refers to the rejection of parental strain bone marrow cells by natural killer cells of mice that are F1 hybrids derived from two inbred parental strains. This pattern of rejection is not seen in solid organ transplants. Progress in understanding this exception to the laws of transplantation genetics has occurred with the recent discovery of negative signaling receptors for MHC class I molecules. In the last year the discovery of natural killer cell subsets with non-overlapping inhibitory receptors for parental class I molecules has provided an explanation for hybrid resistance. In some instances, however, positive rather than negative signaling seems to be the basis for rejection of allogeneic as well as parental marrow cell grafts.

Cognitive impairment in Schwartz-Jampel syndrome: a case study

Schwartz-Jampel syndrome (SJS) is a rare, hereditary neuromuscular disorder. The prevalence of mental retardation has been estimated at 25%, however, no etiologic cause has been described. Neuropsychologic and speech language evaluations of an 8-year-old boy with SJS showed a developmental language disorder and attention deficit disorder. He performed in the impaired range on linguistic/sequential information processing tests while performing in the average range in visuoperceptual and nonverbal tests of intelligence and memory. These results suggest further investigation of the cognitive and language functioning of patients with SJS.

Allorecognition by murine natural killer cells: lysis of T-lymphoblasts and rejection of bone-marrow grafts

Natural killer (NK) cells of inbred mice reject allogeneic bone-marrow cells, and NK cells of F1 hybrid mice can reject parental bone-marrow cells (hybrid resistance). In some cases these patterns of rejection can be mimicked in vitro by utilizing IL-2 cultured NK effector cells and allogeneic or parental T-lymphoblasts as target cells. Lysis of allogeneic and parental targets in vitro can be explained on the basis of the missing self hypothesis. Subsets of NK cells that bear non-overlapping MHC class I inhibitory receptors belonging to the Ly49 family lyse allogeneic targets because they do not express self class I molecules of the NK cell donor. Parental strain targets are lysed because they do not express all of the self class I antigens of the F1 hybrid, and hence fail to deliver inhibitory signals to all subsets of F1 NK cells. The expression of Ly49 receptors on NK cells is regulated by host MHC to ensure maximal sensitivity to alterations in self class I molecules and to prevent autoreactivity. In many instances, however, the rejection of allogeneic bone marrow cells in vivo cannot be readily explained by the missing self hypothesis. In these instances, it appears that rejection is initiated by class I MHC receptors on NK cells that recognize allogeneic class I molecules as non-self, and activate rather than inhibit NK cell function.

Association of U2 snRNP with the spliceosomal complex E

In metazoans, the E complex is operationally defined as an ATP-independent spliceosomal complex that elutes as a single peak on a gel filtration column and can be chased into spliced products in the presence of an excess of competitor pre-mRNA. The A complex is the first ATP-dependent functional spliceosomal complex. U1 snRNP first binds tightly to the 5'splice site in the E complex and U2 snRNP first binds tightly to the branch site in the A complex. In this study, we have generated and characterized a monoclonal antibody (mAb 4G8) directed against SAP 62, a component of U2 snRNP and a subunit of the essential mammalian splicing factor SF3a. We show that this antibody is highly specific for SAP 62, detecting only SAP 62 on Western blots and immunoprecipitating only SAP 62 from nuclear extracts. The anti-SAP 62 antibody also immunoprecipitates U2 snRNP and the A complex. Significantly, however, we find that the E complex is also efficiently immunoprecipitated by the anti-SAP 62 antibody. This antibody does not cross-react with any E complex-specific components, indicating that SAP 62 itself is associated with the E complex. To determine whether other U2 snRNP components are associated with the E complex, we used antibodies to the U2 snRNP proteins B"and SAP 155. These antibodies also specifically immunoprecipitate the E complex. These observations indicate that U2 snRNP is associated with the E complex. However, we find that U2 snRNP is not as tightly bound in the E complex as it is in the A complex. The possible significance of the weak association of U2 snRNP with the E complex is discussed.

Cowpox in British voles and mice

Serosurveys indicate that bank voles, field voles and woodmice are probably reservoir hosts of cowpox virus in western Europe, although virus has not yet been isolated from these species. In this study, bank voles, field voles, woodmice and laboratory mice were shown to be susceptible to combined intradermal and subcutaneous inoculation with 3-20 plaque-forming units (pfu) of cowpox virus. Bank and field voles, but not laboratory mice, were also susceptible to combined oral and nasal inoculation with 50 pfu. Few clinical signs were seen and virus was generally recovered only from inoculation sites. Bank voles were not susceptible to injection of ectromelia virus (5000 pfu) into the skin (as described above). These results provide information on which further pathogenesis and transmission studies can be based, and support the view that the orthopoxvirus antibody detected in British wild voles and woodmice indicates infection with cowpox virus. However, further investigation of the pathogenesis of cowpox in these species is needed to understand better the epidemiology of the disease.

Phenotypic and functional characterization of long-lived NK cell lines of different maturational status obtained from mouse fetal liver

Culture of day 14 mouse fetal liver (FL) cells in high dose IL-2, together with appropriate combinations of IL-4 and PMA, resulted in the generation of cell lines, termed FL-A lines, that were phenotypically and functionally indistinguishable from cultured adult splenic NK cell populations with the single important exception that no Ly49-expressing cells were present. By contrast, when FL cells were cultured in low-dose IL-2 alone, a second population of slow-growing NK-like cells, termed FL-B cells, emerged. These cells expressed the NK markers asialoGM1, 10A7, 2B4, and Fc gammaRII/III but differed from FL-A and splenic NK cells in expressing IL-2R alpha and stem cell factor receptor (SCFR) but no B220. Most lines derived in this manner had minimal or no cytolytic activity and only very low levels of NK1.1. However, they could secrete substantial quantities of several lymphokines including IL-3, granulocyte-macrophage (GM)-CSF, TNF-alpha, and, most surprisingly, IL-2. A minority of FL-B lines, typified by line 903, displayed marked cytolytic activity, moderate levels of NK1.1, reduced production of IL-2, and the capacity for accelerated growth in high-dose IL-2. FL-B lines generally expressed mRNA for CD3gamma but not for other CD3 chains, whereas FL-A and fetal thymic (FT) NK lines often expressed mRNA for all four CD3 chains. Despite many similarities to pro-T cells, FL-B cells showed no capacity to differentiate into mature T cells. Taken together, our results suggest that NK lines of different maturity can be obtained from fetal liver, with FL-B lines being the most immature, FL-A lines the most mature, and lines such as FL-B 903 representing an intermediate state of differentiation.

Phenotypic and functional characterization of long-lived NK cell lines of different maturational status obtained from mouse fetal liver

Culture of day 14 mouse fetal liver (FL) cells in high dose IL-2, together with appropriate combinations of IL-4 and PMA, resulted in the generation of cell lines, termed FL-A lines, that were phenotypically and functionally indistinguishable from cultured adult splenic NK cell populations with the single important exception that no Ly49-expressing cells were present. By contrast, when FL cells were cultured in low-dose IL-2 alone, a second population of slow-growing NK-like cells, termed FL-B cells, emerged. These cells expressed the NK markers asialoGM1, 10A7, 2B4, and Fc gammaRII/III but differed from FL-A and splenic NK cells in expressing IL-2R alpha and stem cell factor receptor (SCFR) but no B220. Most lines derived in this manner had minimal or no cytolytic activity and only very low levels of NK1.1. However, they could secrete substantial quantities of several lymphokines including IL-3, granulocyte-macrophage (GM)-CSF, TNF-alpha, and, most surprisingly, IL-2. A minority of FL-B lines, typified by line 903, displayed marked cytolytic activity, moderate levels of NK1.1, reduced production of IL-2, and the capacity for accelerated growth in high-dose IL-2. FL-B lines generally expressed mRNA for CD3gamma but not for other CD3 chains, whereas FL-A and fetal thymic (FT) NK lines often expressed mRNA for all four CD3 chains. Despite many similarities to pro-T cells, FL-B cells showed no capacity to differentiate into mature T cells. Taken together, our results suggest that NK lines of different maturity can be obtained from fetal liver, with FL-B lines being the most immature, FL-A lines the most mature, and lines such as FL-B 903 representing an intermediate state of differentiation.

IL-15 can substitute for the marrow microenvironment in the differentiation of natural killer cells

NK cells require an intact bone marrow microenvironment to acquire lytic function. In mice rendered osteopetrotic by 17beta-estradiol treatment, NK1.1 positive cells are arrested in a nonlytic state. Culture with as little as 2 ng/ml of murine IL-15 (mIL-15), a cytokine produced by macrophages and stromal cells, causes these immature NK1.1+ cells to acquire lytic activity. By contrast, approximately 10- to 50-fold greater amount of mIL-2 was required to induce similar level of cytotoxicity. After culture with mIL-15, the relatively low expression of B220, CD11b, and Ly-49 molecules on immature NK1.1+ cells was increased to levels comparable to those of mature splenic NK1.1+ cells. mIL-15 also caused a greater expansion of NK1.1+CD3- cells as compared with NK1.1+CD3+ cells. We conclude that IL-15 is a specific maturation factor for NK cells and that it can mimic the marrow microenvironment in vitro.

IL-15 can substitute for the marrow microenvironment in the differentiation of natural killer cells

NK cells require an intact bone marrow microenvironment to acquire lytic function. In mice rendered osteopetrotic by 17beta-estradiol treatment, NK1.1 positive cells are arrested in a nonlytic state. Culture with as little as 2 ng/ml of murine IL-15 (mIL-15), a cytokine produced by macrophages and stromal cells, causes these immature NK1.1+ cells to acquire lytic activity. By contrast, approximately 10- to 50-fold greater amount of mIL-2 was required to induce similar level of cytotoxicity. After culture with mIL-15, the relatively low expression of B220, CD11b, and Ly-49 molecules on immature NK1.1+ cells was increased to levels comparable to those of mature splenic NK1.1+ cells. mIL-15 also caused a greater expansion of NK1.1+CD3- cells as compared with NK1.1+CD3+ cells. We conclude that IL-15 is a specific maturation factor for NK cells and that it can mimic the marrow microenvironment in vitro.

Diagnosing HIV dementia: a retrospective analysis

The purpose of this study was to determine the criteria by which the diagnosis of HIV dementia was made by providers in a public HIV outpatient clinic and hospital, and to evaluate the extent to which the providers' diagnosis confirmed or denied the presence of HIV dementia according to CDC recommendations. Retrospective chart analysis was conducted detailing symptomology, laboratory findings, and social characteristics of 103 HIV-infected patients from Nov 1, 1990 to Dec 31, 1993. Seventy-eight patients were evaluated by providers and given a preliminary HIV dementia diagnosis; 25 patients received no preliminary diagnosis. On follow-up, 39 were confirmed diagnosis while 64 patients received no follow-up (confirmatory) diagnosis. Inability to pay attention or remember details, memory deficit, motor weakness, and mild disorientation were all found to be significantly associated with being evaluated by a provider. Substance use was prevalent. Inconsistent manner in which HIV-demented patients were identified highlights the need for a standardized evaluation of signs and symptoms known to be associated with HIV dementia.

Children's understanding of the distinction between real and apparent emotions: a training study

The effects of two types of training on 4-year-old children's understanding of the distinction between experienced positive affect and neutral or negative display were examined. One type of training provided first-hand experience of possible discrepancies between facial expression and actual affect. The other training focused on the sorts of motives that might prompt the concealment of positive affect. Compared with a control group, both experimental groups showed modest gains.

Others' actions can reflect on the self: a developmental study of extended identity

This study was an investigation of children's understanding that others' judgments of the self can be based on the actions of another person with whom one is associated. Five-, 8-, and 11-year-old children in Scotland were presented with hypothetical scenarios that indicated that they were responsible for a toddler who breached normative expectations of behavior. The children were required to make a variety of judgments, most notably concerning their likely emotion and its causes, and what others would think of them. The majority recognized that others would make negative judgments of the self. However, emotional self-attributions indicated that only among the 11-year-olds was there a widespread tendency to be self-punitive-that is, to attribute reflexive emotions such as embarrassment. Particularly among the 5-year-olds, punitive responses (e.g., anger) were directed only at the norm-violating toddler, implying that, unlike the oldest children, they did not view the toddler as constituting part of their extended identity. Eight-year-olds appeared to represent an intermediate step between the younger and older groups. In the light of these findings it is suggested that a mature form of extended identity may be a relatively late development.

Feline calicivirus strain differentiation using monoclonal antibody analysis in an enzyme-linked immuno-flow-assay

Six monoclonal antibodies raised against feline calicivirus (FCV) strain F9 were used in an enzyme-linked immuno-flow-assay (ELIFA) to analyse 55 isolates of FCV. Forty seven field isolates were obtained from cats with acute oral/respiratory disease, chronic oral lesions, and from cats showing vaccine reactions, i.e. clinical signs of FCV infection shortly after vaccination. Eight reference strains including F9 and three vaccine strains based on F9 were also examined. All of the strains of F9, derived from various sources, reacted with all six of the monoclonal antibodies, whereas some of the field isolates did not react with any. In general, the field isolates showed a spectrum of reactivities and selected isolates could be distinguished. However, there were no clear cut differences between the clinical groups. Overall, the oral/respiratory group showed less reactivity with the monoclonals, suggesting they were less related to F9. Although the other groups appeared to be more closely related to F9, none of the isolates tested reacted with all six monoclonal antibodies.

Identification of proteins that interact with exon sequences, splice sites, and the branchpoint sequence during each stage of spliceosome assembly

We have carried out a systematic analysis of the proteins that interact with specific intron and exon sequences during each stage of mammalian spliceosome assembly. This was achieved by site-specifically labeling individual nucleotides within the 5' and 3' splice sites, the branchpoint sequence (BPS), or the exons with 32P and identifying UV-cross-linked proteins in the E, A, B, or C spliceosomal complex. Significantly, two members of the SR family of splicing factors, which are known to promote E-complex assembly, cross-link within exon sequences to a region approximately 25 nucleotides upstream from the 5' splice site. At the 5' splice site, cross-linking of the U5 small nuclear ribonucleoprotein particle protein, U5(200), was detected in both the B and C complexes. As observed in yeast cells, U5(200), also cross-links to intron/exon sequences at the 3' splice site in the C complex and may play a role in aligning the 5' and 3' exons for ligation. With label at the branch site, we detected three distinct proteins, designated BPS72,BpS70, and BPS56, which replace one another in the E, A, and C complexes. Another dynamic exchange was detected with pre-mRNA labeled at the AG dinucleotide of the 3' splice site. In this case, a protein, AG100,cross-links in the A complex and is replaced by another protein, AG75, in the C complex. The observation that these proteins are specifically associated with critical pre-mRNA sequence elements in functional complexes at different stages of spliceosome assembly implicates roles for these factors in key recognition events during the splicing pathway.

Proliferation indexes--a comparison between cutaneous basal and squamous cell carcinomas

AIMS

To compare differences in cell proliferation indexes and apoptotic indexes between cutaneous basal and squamous cell carcinomas, in an attempt to suggest an explanation for the differences in their biological behaviour.

METHODS

Forty cases of cutaneous basal cell carcinoma (BCC) and 40 cases of moderately and well differentiated squamous cell carcinoma (SCC) were retrieved from the archives. Sections, 4 microns thick, were cut from formalin fixed, paraffin wax embedded tissue in each case and stained with haematoxylin and eosin. These were then examined for mitotic and apoptotic figures per 1000 cells. Sections from the same cases were also immunostained with the mouse monoclonal antibody Ki67 (MIB1); positive nuclear staining was counted per 1000 cells.

RESULTS

No significant differences were found between the mitotic indexes and apoptotic indexes in these tumours. There was, however, a significant difference in Ki67 (MIB1) staining, with greater staining in the squamous cell carcinomas.

CONCLUSION

Estimation of the mitotic and apoptotic indexes did not reveal any differences between these two tumour types. The proliferation indexes, assessed by Ki67 immunostaining, did differ. This may be one of the factors underlying the more aggressive behaviour of SCC.