Two clusters of Toscana virus meningo-encephalitis in Livorno Province and Elba Island, July-September 2018

BACKGROUND

Toscana virus (TOSV) is an arbovirus transmitted to humans by Phlebotomus spp sandflies. It causes aseptic meningitis and meningoencephalitis with marked seasonality. Here we describe the clinical, microbiological and epidemiological features of two clusters of cases occurred in Tuscany in 2018.

METHODS

A confirmed case was defined as the detection of anti-TOSV IgM and IgG in serum sample, in presence of typical clinical manifestations. We consulted hospital records of hospitalized patients to collect clinical information and obtained epidemiological information from the local health authority investigation report. We telephonically interviewed patients using a standard questionnaire for a 6 months follow-up.

RESULTS

A total of 12 cases of TOSV meningo-encephalitis with onset between 4th of July and 12th of September accessed health care services in the province of Livorno. Eight cases were males with median age 41,5 and four were not resident in the area. Serological investigations confirmed a recent TOSV infection. Eight cases reported visiting Elba Island and four had a possible occupational-related exposure.

CONCLUSIONS

This surge of infection emphasizes the need of information campaigns coupled with adequate surveillance and control interventions against TOSV that, among other arboviruses, is a growing issue of concern in Italy.

Graves' orbitopathy, idiopathic orbital inflammatory pseudotumor and Epstein-Barr virus infection: a serological and molecular study

OBJECTIVE

One of the hypotheses on the pathogenesis of autoimmune diseases, including Graves' disease (GD) and Graves' orbitopathy (GO), involves bacterial or viral infections. Recently, Epstein-Barr virus (EBV) has been proposed to play a role in the pathogenesis of idiopathic orbital inflammatory pseudotumor (IOIP) in Asians. The aim of the present study was to investigate the possible association of GO with EBV infection/exposure, as compared with IOIP, using serum and tissue samples, as well as primary cultures of orbital fibroblasts.

METHODS

Thirty-one patients were studied, including four with IOIP, ten with GO, nine with GD without GO and eight control patients without IOIP, GD and GO. All patients with IOIP and GO underwent orbital decompression. Control patients underwent palpebral surgery. Fibroadipose orbital tissue samples were collected. Serum anti-EBV antibodies were measured in all patients. EBV-DNA was measured in blood samples, orbital tissue samples and primary cultures of orbital fibroblasts.

RESULTS

Serum assays showed that the vast majority of patients have had a previous exposure to EBV, but no one had an acute infection. EBV-DNA was detected in ~40% of blood samples from GO, GD and control patients, but in none of the IOIP samples. EBV-DNA was not detected in any of the orbital tissue samples tested or in primary cultures of orbital fibroblasts.

CONCLUSIONS

EBV infection does not seem to be associated with GD, GO and IOIP in Caucasians. Whether EBV is involved in IOIP in Asians or other populations remains to be confirmed.

Absence of xenotropic murine leukemia virus-related virus in Italian patients affected by chronic fatigue syndrome, fibromyalgia, or rheumatoid arthritis

The xenotropic murine leukemia virus-related virus (XMRV) has been recently linked to chronic fatigue syndrome in a US cohort in whom the virus was demonstrated in 67% patients vs 3.7% healthy controls. Albeit this finding was not substantiated by subsequent reports and eventually considered a laboratory contamination, the matter is still the object of intense debate and scrutiny in various cohorts of patients. In this work we examined well-clinically characterized Italian patients affected by chronic fatigue syndrome, and also fibromyalgia and rheumatoid arthritis, two chronic illnesses of basically unknown etiology which show quite a few symptoms in common with chronic fatigue syndrome. Although we used recently updated procedures and controls, the XMRV was not found in 65 patients with chronic fatigue syndrome diagnosis, 55 with fibromyalgia, 25 with rheumatoid arthritis, nor in 25 healthy controls. These results add to the ever-growing number of surveys reporting the absence of XMRV in chronic fatigue syndrome patients and suggest that the virus is also absent in fibromyalgia and rheumatoid arthritis.

Xenotropic murine leukaemia virus-related virus is not found in peripheral blood cells from treatment-naive human immunodeficiency virus-positive patients

The human pathogen xenotropic murine leukaemia virus-related virus (XMRV) has been tentatively associated with prostate cancer and chronic fatigue syndrome. Unfortunately, subsequent studies failed to identify the virus in various clinical settings. To determine whether XMRV circulates in humans and the relationship with its host, we searched for the virus in 124 human immunodeficiency virus-infected patients who might have been exposed to XMRV, might be prone to infection as a result of progressive immunodeficiency, and had not yet been treated with antiretroviral drugs. Using nested PCR and single-step TaqMan real-time PCR, both designed on the XMRV gag gene, we could not find any positive samples. These findings add to the growing amount of scepticism regarding XMRV.

Effects of feline immunodeficiency virus on feline monocyte-derived dendritic cells infected by spinoculation

During type 1 human immunodeficiency virus infection, not only can dendritic cells (DCs) prime T cells against the virus, but they can also infect them in trans. Feline AIDS is caused by feline immunodeficiency virus (FIV) and is considered a model for the human illness because the two diseases have many features in common. Little is known about the interaction of feline DCs with FIV; therefore, this study attempts to tackle such an issue. Infection of feline monocyte-derived DCs (MDDCs) was attempted by spinoculation with FIV strains Petaluma (FIV-Pet) and M2. FIV-Pet was released rapidly in the supernatants of both infected MDDCs and activated T cells after spinoculation. It is shown that FIV-Pet was produced by MDDCs by monitoring viral content in the supernatants of infected MDDCs, by intracellular staining for p25 and by showing its cytopathic effect. Although activated T cells were better substrates for FIV replication, leading to prolonged viral shedding, both immature MDDCs and MDDCs matured with lipopolysaccharide supported virus production, mostly during the first 2 days after infection. At later times, FIV induced syncytium formation by MDDCs. Concerning the FIV receptors, MDDCs were shown to be CD134-negative and CXCR4-positive, a phenotype compatible with permissiveness to FIV-Pet. These results also suggest that maturation is not hampered by FIV infection and that virus exposure itself does not induce MDDC maturation. It is also shown that infected MDDCs can infect activated PBMCs efficiently in trans. It is concluded that MDDCs can be infected by FIV, although infection does not appear to influence their functionality.

Evaluation of feline immunodeficiency virus ORF-A mutants as candidate attenuated vaccine

Feline immunodeficiency virus (FIV) made defective in the accessory gene ORF-A were previously shown to be greatly attenuated in its ability to replicate in lymphocytes but to grow normally or near normally in other cell types. Here, we examined whether FIV thus mutated could protect specific pathogen-free cats against challenge with ex vivo fully virulent homologous virus. No reversion of the vaccinating infections to wild type ORF-A was noted over 22 months of in vivo infection. Following challenge, 6/6 unvaccinated control cats became readily and heavily infected. In contrast, 3/9 vaccinees showed no evidence of the challenge virus over a 15-month observation period. In the other vaccinees, the challenge virus was predominant for various periods of time, but pre-existing viral loads and CD4 lymphocyte counts were either unaffected or altered only marginally and transiently. These findings show that ORF-A-defective FIV should be further examined as a candidate live attenuated vaccine.

Development of feline immunodeficiency virus ORF-A (tat) mutants: in vitro and in vivo characterization

A functional ORF-A is essential for efficient feline immunodeficiency virus replication in lymphocytes. We have characterized a series of mutants of the Petaluma strain, derived from p34TF10 and having different combinations of stop codons and increasingly long deletions in ORF-A. Six clones proved fully replicative in fibroblastoid Crandell feline kidney cells and monocyte-derived macrophage cultures but failed to replicate in T cell lines and primary lymphoblasts. Cats inoculated with three selected mutants had considerably milder infections than controls given intact ORF-A virus. In vivo, the mutants maintained growth properties similar to those in vitro for at least 7 months, except that replication in lymphoid cells was strongly reduced but not ablated. One mutant underwent extensive ORF-A changes without, however, reverting to wild-type. Antiviral immune responses were feeble in all cats, suggesting that viral loads were too low to represent a sufficiently powerful antigenic stimulus.

Densitometric analysis of Western blot assays for feline immunodeficiency virus antibodies

Western blot (WB) strips for antibodies directed to feline immunodeficiency virus (FIV) were analysed using reflectance densitometry by a semiautomatic densitometer. This method was used to quantify the antibody responses to different FIV proteins in both vaccinated and naturally or experimentally-infected cats. In order to increase reproducibility, reagents and protocols were accurately standardised and internal controls were added. In a first format, an internal control band consisting of feline IgG was added to each blot to minimise the effect of band intensity variation. In a second format, antibody concentrations were calculated from the ratio of the densities produced by test sera and by positive and negative standard sera. The sera under scrutiny were also examined by standard enzyme-linked immunosorbent assay (ELISA) and the results obtained compared with those of the corresponding WB. A statistically significant positive correlation was found between the results obtained with the two methods, and this was especially evident when ELISA titres were compared to corrected WB values (P = 0.001). Densitometric analysis of WB assays allowed to quantify the antibodies against FIV proteins and might be useful to investigate possible humoral immune correlates of protection in FIV vaccination studies and antibody production in the early phase of infection. The quantitation of antibodies to Gag and Env FIV antigens might be used to obtain further informations on the course of FIV disease, as previously demonstrated in human immunodeficiency virus-1 (HIV-1) infections.

[The transplant coordinator]

Spain was the first European country adopting a strategy of organ procurement based on a specific health professional named transplant coordinator, who was first established in Catalunya in the middle eighties. In principle, the transplant coordinator is a doctor with hospital experience who is involved full time in organ procurement. The transplant coordination activity is available without interruption, due to a team work. Transplant coordination is based on four main functions: clinical, research, training and communication, management. The principles of transplant coordination according to the Spanish model are reported in the recently approved Italian law on transplantation (law 91/1999), indicating the coordinator's specific functions: a) communication to the regional reference centre of the data concerning the possible organ donors, b) preparation of the documents needed, c) relationship with the donors' family, d) information and education of the population on transplantation issues.

Immunogenicity of an anti-clade B feline immunodeficiency fixed-cell virus vaccine in field cats

Attempts at vaccine development for feline immunodeficiency virus (FIV) have been extensive, both because this is a significant health problem for cats and because FIV may be a useful vaccine model for human immunodeficiency virus. To date, only modest success, producing only short-term protection, has been achieved for vaccine trials in controlled laboratory settings. It is unclear how relevant such experiments are to prevention of natural infection. The current study used a vaccine that employs cell-associated FIV-M2 strain fixed with paraformaldehyde. Subject cats were in a private shelter where FIV was endemic, a prevalence of 29 to 58% over an 8-year observation period. Cats roamed freely from the shelter through the surrounding countryside but returned for food and shelter. After ensuring that cats were FIV negative, they were immunized using six doses of vaccine over a 16-month period and observed for 28 months after the initiation of immunization. Twenty-six cats (12 immunized and 14 nonimmunized controls) were monitored for a minimum of 22 months. Immunized cats did not experience significant adverse effects from immunization and developed both antibodies and cellular immunity to FIV, although individual responses varied greatly. At the conclusion of the study, 0 of 12 immunized cats had evidence of FIV infection, while 5 of 14 control cats were infected. Thus, the vaccine was safe and immunogenic and did not transmit infection. Furthermore, vaccinated cats did not develop FIV infection in a limited clinical trial over an extended time period. Thus, the data suggest that a fixed, FIV-infected cell vaccine has potential for preventing natural FIV infection in free-roaming cats.

AIDS vaccination studies using feline immunodeficiency virus as a model: immunisation with inactivated whole virus suppresses viraemia levels following intravaginal challenge with infected cells but not following intravenous challenge with cell-free virus

The feline immunodeficiency virus (FIV) provides an excellent model system for AIDS vaccination studies. In the present experiments we investigated the immunogenicity and the protective activity of two inactivated vaccines prepared from a primary virus isolate. One vaccine was composed of whole virus inactivated with paraformaldehyde and then purified (WIV) and the other of viral proteins extracted with Tween-ether (TEV). Both vaccines elicited robust antiviral responses, but neither conferred appreciable levels of resistance against systemic challenge with the homologous virus. In addition, we tested whether the WIV vaccine, that had appeared more immunogenic, could protect against nontraumatic intravaginal exposure to FIV-infected cells. Although the proportions of control and vaccinated animals that became infected following mucosal challenge were similar, the vaccinees had significantly lower viral burdens than the controls, thus suggesting that immunisation with the WIV vaccine had limited FIV replication following intravaginal challenge.

Polyneuropathy in autosomal dominant cerebellar ataxias: phenotype-genotype correlation

Autosomal dominant cerebellar ataxias (ADCAs) are clinically and genetically heterogeneous neurodegenerative disorders. The aim of this study was to evaluate electrophysiologically peripheral nervous system involvement in each of the groups studied and its correlation with the number of CAG repeats. Forty patients with ADCA were clinically and electrophysiologically investigated. Thirty-five patients belonged to the ADCA type I group (SCA1, 12; SCA2, 10; SCA3, 13) and five to the ADCA type II group. Axonal sensory or sensorimotor polyneuropathy was found in 42% of the SCA1 patients, 80% of the SCA2 patients, and 54% of the SCA3 patients, whereas electrophysiological studies were normal in all those with ADCA type II. The number of CAG repeats was significantly higher in SCA1 patients with polyneuropathy than in those without polyneuropathy (P = 0.01), whereas the reverse was observed in SCA3/MJD (Machado-Joseph disease) patients (P = 0.05). We conclude that axonal polyneuropathy is often associated with ADCA type I, but its frequency varies according to factors such as the locus responsible and the number of CAG repeats.

Kinetics of replication of a partially attenuated virus and of the challenge virus during a three-year intersubtype feline immunodeficiency virus superinfection experiment in cats

The effects of preinfecting cats with a partially attenuated feline immunodeficiency virus (FIV) on subsequent infection with a fully virulent FIV belonging to a different subtype were investigated. Eight specific-pathogen-free cats were preinfected with graded doses of a long-term in vitro-cultured cell-free preparation of FIV Petaluma (FIV-P, subtype A). FIV-P established a low-grade or a silent infection in the inoculated animals. Seven months later, the eight preinfected cats and two uninfected cats were challenged with in vivo-grown FIV-M2 (subtype B) and periodically monitored for immunological and virological status. FIV-P-preinfected cats were not protected from acute infection by FIV-M2, and the sustained replication of this virus was accompanied by a reduction of FIV-P viral loads in the peripheral blood mononuclear cells and plasma. However, from 2 years postchallenge (p.c.) until 3 years p.c., when the experiment was terminated, preinfected cats exhibited reduced total viral burdens, and some also exhibited a diminished decline of circulating CD4(+) T lymphocytes relative to control cats infected with FIV-M2 alone. Interestingly, most of the virus detected in challenged cats at late times p.c. was of FIV-P origin, indicating that the preinfecting, attenuated virus had become largely predominant. By the end of follow-up, two challenged cats had no FIV-M2 detectable in the tissues examined. The possible mechanisms underlying the interplay between the two viral populations are discussed.

AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: detailed analysis of the humoral immune response to a protective vaccine

The feline immunodeficiency virus (FIV) cat model is extensively used to investigate possible vaccination approaches against AIDS in humans. Although consistent levels of protection have been achieved with FIV, as with other model systems, by immunizing with whole inactivated virus or fixed infected cells, the mechanisms responsible for protection are elusive. In previous studies we showed that cats immunized with a vaccine consisting of fixed infected cells were protected or unprotected against cell-free or cell-associated FIV challenge depending on the time interval between completion of vaccination and challenge. In an attempt to define possible humoral immune correlates of protection, selected sera harvested at the times of challenge from such cats were examined for anti-FIV-antibody titers and properties by using binding and functional immunological assays. Binding assays included quantitative Western blotting, enzyme-linked tests for antibodies to FIV glycoproteins and immunodominant linear epitopes, and tests for measuring conformation dependence and avidity of anti-viral-envelope antibodies. Functional assays included virus neutralization performed with two different cell substrates, complement- and antibody-dependent virolysis, blocking of reverse transcriptase, and an assay that measured the ability of sera to prevent FIV growth in cocultures of infected and uninfected cells. Despite the wide spectrum of parameters investigated, no correlation between vaccine-induced protection and the humoral parameters measured was noted.

AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: homologous erythrocytes as a delivery system for preferential immunization with putative protective antigens

Feline immunodeficiency virus (FIV) is a useful model for testing of criteria for AIDS vaccine development. In the protocol we adopted, we used a primary isolate of FIV as a source of antigen and, for challenge, plasma from cats infected with the homologous virus never passaged in vitro. Cat erythrocytes (RBC) were coated with the surface components of freshly harvested and purified FIV by means of biotin-avidin-biotin bridges and used to immunize specific-pathogen-free cats (four doses at monthly intervals; total amount of FIV antigen administered per cat, approximately 14 microg). Immunized cats developed moderate levels of antibodies directed mainly to surface components of the virion and clearly evident lymphoproliferative responses. Four months after the last dose of immunogen, FIV-immunized cats and control cats immunized with bovine serum albumin-coated RBC were challenged. Judged from the results of the subsequent 12-month follow-up, FIV-immunized cats exhibited at least some degree of protection. However, following rechallenge, most of the FIV-immunized animals became virus positive in spite of a booster immunogen dose given 2 months before the second challenge.

Studies of AIDS vaccination using an ex vivo feline immunodeficiency virus model: protection conferred by a fixed-cell vaccine against cell-free and cell-associated challenge differs in duration and is not easily boosted

Cats immunized with cells infected with a primary isolate of feline immunodeficiency virus (FIV) and fixed with paraformaldehyde were challenged with cell-free or cell-associated homologous virus obtained ex vivo. Complete protection was observed in animals challenged with cell-free virus 4 months after completion of vaccination (p.v.) or with cell-associated virus 12 months p.v. In contrast, no protection was observed in cats challenged with cell-free virus 12 or 28 months p.v. or with cell-associated virus 37.5 months p.v. Prior to the 28- and 37.5-month challenges, the animals had received a booster dose of vaccine that had elicited a robust anamnestic immune response. These results show that vaccine-induced protection against ex vivo FIV is achievable but is relatively short-lived and can be difficult to boost.

Genetic diversity of feline immunodeficiency virus: dual infection, recombination, and distinct evolutionary rates among envelope sequence clades

For the rapid genetic analysis of feline immunodeficiency virus (FIV), we developed a heteroduplex mobility assay (HMA) that utilizes a PCR-amplified fragment of the FIV envelope gene spanning the third and fourth variable regions of the envelope surface protein coding sequence. Viral sequences were successfully amplified from blood specimens from 98 naturally infected cats from Australia, Canada, Germany, Italy, South Africa, and the United States. Eighty were clearly assignable to the A or B envelope sequence subtypes. Three belonged to subtype C, one was dually infected with viruses harboring the A and B env subtypes, and several were categorized as outliers to any of the established subtypes or as probable intersubtype recombinants. Some geographic clustering was evident, with subtypes A and B found in greater frequency in the western and eastern regions of the United States, respectively. Subtypes A, B, and C were found on more than one continent, and countries with more than two samples analyzed contained at least two subtypes. The broadest representation of subtypes was found in Munich, Germany, where three subtypes and one virus that was not classifiable by HMA were found. Thirteen samples were selected for DNA sequence determination over the same region of env used for HMA. Analysis of all available FIV env sequences from this and previous studies revealed the existence of recombinant viruses generated from subtype A/B, B/D, and A/C envelope gene sequences. Subtype A env sequences were less diverse than subtype B sequences, although both groups had well-supported clusters. Furthermore, the mutational pattern giving rise to diversification in the two subtypes differed, with the subtype A viruses showing half as many synonymous site mutations compared to subtype B yet showing similar levels of nonsynonymous site changes. These results are consistent with the hypothesis that FIV-B is an older virus group and is possibly more host adapted than FIV-A.

Incubation time for feline immunodeficiency virus cultures

In a recent report, Fiscus et al. (S. A. Fiscus, S. L. Welles, S. A. Spector, and J. L. Lathey, J. Clin. Microbiol. 33:246-247, 1995) have shown that qualitative human immunodeficiency virus cultures can be terminated at day 21 with minimal false-negative results. We have evaluated a large number of qualitative and quantitative feline immunodeficiency virus (FIV) isolations to determine how long FIV cultures should be incubated to obtain reasonably certain results. The rate at which FIV cultures became positive was influenced by whether the cats under study were naturally or experimentally infected, the duration of in vivo infection, and the number of infected peripheral blood mononuclear cells seeded. The results show that cultures for FIV isolation should be kept for 5 to 6 weeks.

Inhibition of feline immunodeficiency virus infection in vitro by envelope glycoprotein synthetic peptides

Sixty-six 20- to 23-amino-acid synthetic peptides, partially overlapping by 10-12 amino acids, spanning the entire sequence of the envelope SU and TM glycoproteins of the Petaluma isolate of FIV, have been used to investigate the Env domains involved in viral infection. Peptides 5 to 7, spanning amino acids 225E-P264 located in a conserved region of the SU protein, and peptides 58 to 61, spanning amino acids 767N-P806 and encompassing hypervariable region 8 of TM protein, exhibited a remarkable and specific antiviral effect against the homologous and one heterologous isolate, as judged by inhibition of FIV-induced syncytium formation and p25 production in CrFK cells. Peptides 5 and 7, but not peptides 58 and 59, also inhibited viral replication of a fresh FIV isolate on nontransformed lymphoid cells. By flow cytometry, peptides 5, 7, 58, and 59 were shown to bind the surface of FIV permissive cells. The antiviral activity of peptides 5 and 7, however, was time-dependent, as inhibition of FIV replication was seen when the peptides were administered before or within 3 hr after virus inoculation; in contrast, TM peptides 58 and 59 exerted a potent inhibitory effect when added up to 24 hr after virus inoculation. Circular dychroism analysis showed that peptide 5 folds to a helical conformation in the presence of a hydrophobic environment. Although the basis for the antiviral action of the peptides is not understood, our data suggest that the inhibitory peptides may act by interacting with cell-surface molecules involved in viral infection.

Vaccination protects against in vivo-grown feline immunodeficiency virus even in the absence of detectable neutralizing antibodies

So far, vaccination experiments against feline immunodeficiency virus have used in vitro-grown virus to challenge the vaccinated hosts. In this study, cats were vaccinated with fixed feline immunodeficiency virus-infected cells and challenged with plasma obtained from cats infected with the homologous virus diluted to contain 10 cat 50% infectious doses. As judged by virus culture, PCRs, and serological analyses performed over an 18-month period after the challenge, all of the vaccinated cats were clearly protected. Interestingly, prior to challenge most vaccines lacked antibodies capable of neutralizing a fresh isolate of the homologous virus.

The feline lymphoid cell line MBM and its use for feline immunodeficiency virus isolation and quantitation

We report on the development of a feline T lymphoblastoid cell line obtained from the peripheral blood mononuclear cells (PBMC) of a specific pathogen free cat and designated MBM. The cells are pan-T+, CD4- and CD8- and remained interleukin-2-dependent and concanavalin A-dependent throughout the period of observation. MBM cells have proved at least as sensitive as fresh blasts to infection with cell-free stocks of three feline immunodeficiency virus (FIV) isolates. Upon infection, they exhibit a lytic cytopathic effect. Repeated attempts to establish a chronic infection have failed. Using a limiting cell dilution method, it has been shown that MBM cells may be more sensitive than fresh blasts as substrate for isolating FIV from the PBMC of infected cats. These studies have also shown that considerable individual variations exist in the virus loads present in the PBMC of naturally infected cats, and that load size does not appear to correlate with cat age, clinical status, CD4/CD8 ratio and titer of serum neutralizing antibody.

Contribution of known mitogenic signaling pathways to induction of DNA synthesis in quiescent Chinese hamster fibroblasts

The mitogenic pathways so far identified in mammalian cells fall into three main categories: tyrosine kinase, kinase C, and the cAMP-dependent pathways. In quiescent murine 3T3 fibroblasts, all three signaling pathways synergize with each other to restart DNA synthesis. In order to establish if the same was true in other rodent fibroblast lines we studied the effects of factors, known to modulate the above-mentioned pathways, on DNA synthesis in Chinese hamster embryo fibroblasts (CHEF/18). The factors examined were: (1) EGF and insulin representative of tyrosine kinase-activating growth factors, (2) TPA as specific activator of protein kinase C, (3) cholera toxin, dibutyryl cyclic AMP, and theophylline as compounds increasing cAMP levels. We found that EGF alone is a strong mitogen in CHEF/18 cells, probably because it can modulate by itself all three pathways. Although cAMP acts as a growth enhancer in 3T3 cells, in CHEF/18 where high levels of cAMP were found, increased concentrations of this second messenger produce strong DNA synthesis inhibition and temporal disturbance of ribosomal protein S6 phosphorylation. Possible interpretations of these findings are presented.

Familial Parkinson's disease and polymorphism at the CYP2D6 locus

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Serum neutralization of feline immunodeficiency virus is markedly dependent on passage history of the virus and host system

Sera from feline immunodeficiency virus (FIV)-infected cats exhibited extremely low levels of neutralizing antibodies against virus passaged a few times in vitro (low passage), when residual infectivity was assayed in the CD3+ CD4- CD8- MBM lymphoid cell line or mitogen-activated peripheral blood mononuclear cells. By sharp contrast, elevated titers of highly efficient neutralizing activity against FIV were measured, by use of high-passage virus, in assays on either the fibroblastoid CrFK or MBM cell line. However, high-passage virus behaved the same as low-passage virus after one in vivo passage in a specific-pathogen-free cat and reisolation. Subneutralizing concentrations of infected cat sera enhanced the production of low-passage virus by MBM cells, an effect not seen with high-passage virus in CrFK cells. These qualitative and quantitative discrepancies could not be attributed to differences in the amount of immunoreactive viral material, to the amount of infectious virus present in the viral stocks, or to the presence of anti-cell antibodies. The observed effects were most likely due to the different passage history of the viral preparations used. The observation that neutralizing antibodies detected with high-passage virus were broadly cross-reactive in assays with CrFK cells but isolate specific in MBM cells suggests also that the cell substrate can influence the result of FIV neutralization assays. This possibility could not be tested directly because FIV adapted to grow in CrFK cells had little infectivity for lymphoid cells and vice versa. In vitro exposure to infected cat sera had little or no effect on the ability of in vivo-passaged FIV to infect cats. These data reveal no obvious relationship between titers against high-passage virus and ability to block infectivity of FIV in cats and suggest caution in the use of such assays to measure vaccine efficacy. In conclusion, by contrast with what has been previously reported for the use of CrFK cells and high-passage virus, both natural and experimental infections of cats with FIV generate poor neutralizing antibody responses with regard to in vivo protection.

Are the steady state kinetics of glutathione transferase always dependent on the deprotonation of the bound glutathione? New insights in the kinetic mechanism of GST P 1-1

Steady state kinetics measurements performed on human placenta glutathione transferase (GST P 1-1), utilizing 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) as co-substrate, show that the kcat value (approximately equal to 1.2 s-1) is pH-independent between pH 4.0 and 7.0 and is scarcely affected by the nature of the leaving group. The pH profile of kcat/KmNBD-Cl suggests a pKa > or = 6.0 for GSH bound to the enzyme. Pre-steady state experiments demonstrate the presence of a burst-phase in which the conjugation product (or the sigma-complex intermediate) accumulates in an amount stoichiometric to the GST active site concentration. These results indicate that the steady state kinetics of GST P 1-1 with NBD-Cl are independent of the deprotonation of the bound GSH between pH 4.0 and 7.0 because the rate-limiting step is the product release. The occurrence of a fast enzymatic conjugation of GSH with a number of poor substrates or even electrophilic inhibitors of GST, mainly performed in a single turnover reaction, may reveal a further detoxicating role of GST.

Detection of feline immunodeficiency virus in saliva and plasma by cultivation and polymerase chain reaction

The rates of feline immunodeficiency virus (FIV) isolation from saliva, plasma, and peripheral blood mononuclear cells (PBMC) of infected cats were compared; isolation rates were 18, 14, and 81%, respectively, in naturally infected cats and 25, 57, and 100%, respectively, in experimentally infected animals. There was no obvious relationship between isolation rate and clinical stage or between isolation rate and the titer of neutralizing antibody in serum. Virus could be isolated from one salivary gland as early as 1 week postinfection and, on a more regular basis, starting at 3 weeks postinfection, when, however, most other tissues were also positive. Polymerase chain reaction analysis showed that FIV genomes are present in saliva and plasma more frequently than expected on the basis of isolation data. Saliva was also found to contain viral DNA, indicating that it may harbor virus-infected cells as well as free virus. The addition of plasma but not of saliva to PBMC cultures delayed FIV growth. Isolation from plasma may be hampered by FIV neutralizing antibody and by the cytotoxic activity of this fluid for the PBMC used as a cell substrate.

Genetic structure of the human population in the Po delta

The genetic structure of the population of Ferrara Province in the Po delta in Italy was investigated using chi 2 analysis, kinship analysis, analysis of correspondences, and geographical mapping of principal components of gene frequencies. chi 2 Analysis tests for Hardy-Weinberg equilibrium and for heterogeneity of gene and phenotype frequencies; kinship analysis tests for association between indicators of genetic and geographic proximity; analysis of correspondences relates localities and genetic systems in an eigenvectorial space; and geographic mapping displays the principal components of gene frequencies in the real space. In 1,364 adults in 26 residential units, seven presumably neutral isoenzyme systems were typed; ACP1 ESD, GLO I, GPT, PGD, PGM1 and PGP. It was found that average kinship for these neutral systems is correlated with geographic distance in this small area, but not as strongly as kinship for beta-thalassemia. A north-south gradient was observed for ESD. Analysis of correspondences indicated GPT, PGM1, and GLO I as the systems contributing most to differentiation within the province. The maps obtained from principal components of gene frequencies were consistent with the migrational history of the area.

Depression of early phase of HTLV-I infection in vitro mediated by human beta-interferon

Natural human interferon beta (beta-IFN) was tested during the early phase of in vitro infection with HTLV-I virus of human cord blood mononuclear cells (CBL), to evaluate whether its antiviral and immunomodulating effects might prevent spreading of infection in the host. beta-IFN was found to reduce HTLV-I transmission and integration in CBL cultures. Moreover, beta-IFN had no effect in preventing virus transmission and integration in K562 and a very limited effect in HL60 and Molt-4 human tumour lines, suggesting a cell-type specific mode of action. beta-IFN induced a 'priming' response on CBL, since overnight pretreatment of recipient cells or one single treatment at the onset of the coculture were almost equally effective in protecting against HTLV-I infection. During the early days post infection (p.i.), IFN-treated CBL showed a pattern of phenotypic markers that was closer to that of non-infected CBL. In contrast, untreated CBL exposed to HTLV-I showed a percent increase of Tac+, M3+ and Leu 11+ subpopulations. Cell-mediated immune responses of CBL were depressed after coculturing with HTLV-I producer MT-2 cells. beta-IFN was able to boost the cell-mediated cytotoxicity of fresh and infected CBL against both K562 and MT-2 target cells. Leukocyte blastogenesis in mixed lymphocyte/tumour cell cultures, evaluated in terms of 3H-thymidine incorporation during the first week p.i., was also enhanced by IFN when macrophages and lymphocytes were reconstituted at an optimal 1:20 ratio. It is conceivable that this overall enhancement of the immune response induced by beta-IFN could contribute to reduce HTLV-I infection in vitro.

Distribution of enzyme polymorphisms in six Sicilian communes

The relations between seven genetic systems in six Sicilian communes (a commune is the smallest unit in the Italian administrative system) were explored in a sample of 719 young adults. It was found that there is some correspondence between geographic location and genetic differentiation, through kinship analysis and correspondence analysis. A probable bottleneck or mutation effect was observed in the commune of Vizzini, in Southeastern Sicily, which is characterized by a polymorphic frequency of the allele H of 6PGD.

Population structure of Sicily: beta-thalassemia and HbS

The population structure of two alleles with similar characteristics, HbS and beta-thalassemia, was studied in the same area in Sicily. It was observed that beta-thalassemia has uniform frequencies over the island, and that HbS shows a South-North cline. A singularity exists for HbS in the town of Butera, where the frequency of the S gene is six times higher than the island average. It was suggested that HbS entered Sicily from Greece (or directly from North Africa) when the beta-thalassemia allele was already established in the Island.

Sequences coding for the ribosomal protein L14 in Xenopus laevis and Xenopus tropicalis; homologies in the 5' untranslated region are shared with other r-protein mRNAs

In the haploid genome of Xenopus laevis there are two genes coding for the r-protein L14. It is not known if they are located on the same chromosome. cDNA clones deriving from the transcripts of the two genes have been isolated from an oocyte messenger cDNA bank showing that they are both expressed. We have studied the structure of one of the L14 genes by Electron Microscopy, restriction mapping and sequencing. An allelic form of the L14 gene was also isolated. It contains a large deletion covering the 5' end region up to the middle of the third intron. The 5' end of the X. laevis L14 gene was compared to that of the corresponding gene in the closely related species X. tropicalis and found to be highly conserved. The L14 gene has multiple initiation sites, but the large majority of the transcripts start in the middle of a pyrimidine tract not preceded by a canonical TATA box as in other eukaryotic housekeeping genes. The X. laevis L1 and L14 genes have a common decanucleotide in the first exon in the same position with regard to the initiator ATG which just precedes the first intron. The decanucleotide shows homology with the X. laevis 18S rRNA.

A cline for glyoxalase I allele frequencies in Italy

A gradient of glyoxalase I allele frequencies is described in Italian populations. The association between longitude and allele frequency is assessed through simple and multiple correlation, and gene flow is suggested as a major factor in the origin of such a pattern.

Population structure of eastern Sicily

A sample of 465 persons from Eastern Sicily was studied for 11 red-cell enzymes, namely GLO, GPT, EsD, PGP, PGD, Dia, AcP, PGM, SOD, CAI and CAII. The allele frequencies were compared with those of other Italian populations and showed that the island is homogeneous with the mainland for these systems. The rate of heterozygosity was studied as a function of interparental distance; although high (0.77) the correlation did not reach significance.

A new rare variant of the glyoxalase I system of the red cell: GLO-Sicily

A fast variant of the red cell enzyme glyoxalase I was identified in a sample of 663 persons from Eastern Sicily; the allele was designated GLOSi. The gene frequencies for the common alleles GLO1 and GLO2 are not different from those observed in other southern Italian populations, and are in agreement with the hypothesis of a westward gene flow from Asia.