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The role of the Epstein-Barr virus (EBV), a ubiquitous lymphotropic human herpesvirus type 4, in the etiology of nasopharyngeal carcinoma (NPC) is not fully understood. The mechanism of NPC carcinogenesis, associated with the virus, is also not clear. The objective of present investigation was to carry out comparative analysis of the structure of an LMP1 oncogene of EBV in viral isolates obtained from patients with two types of tumors of the oral cavity: (a) associated (i.e., NPC) and (b) not associated (other tumors of the same anatomical region, OTOC) with EBV. Comparative analysis of C-terminal regions of LMP1 variants that was based on a sequence analysis of LMP1 from tumor, blood and throat washing samples of NPC and OTOC patients showed that all structural characteristics of LMP1 in both groups of patients were genetically similar, and differences found between compared parameters were statistically insignificant. Thus, for the first time it has been revealed that in NPC and OTOC patients in Russia genetically related EBV strains with structurally similar LMP1 variants are persisting that are likely to reflect a polymorphism of the virus circulating in population. The findings allow us to suggest that in non-NPC-endemic regions of the world, which include Russia, the risk of NPC development does not depend on the EBVstrain and its variant of LMP1 so much, but mostly from the genetic predisposition of infected persons to the disease and the exposure to other, as yet unknown agents.

The investigation was undertaken to study the molecular characteristics of Epstein-Barr virus (EBV) LMP1 gene samples amplified from the tumor and intact tissues of patients with EBV-negative forms of gastric carcinoma (GC). The genetic structure of these samples determined by their sequencing was compared with that of the gene samples isolated from the cells of oropharyngeal washing specimens from the same patients with GC, as well as peripheral blood lymphocytes of patients with infectious mononucleosis (IM) and blood donors. The findings suggest that the samples of tumor tissue LMP1 from patients with GC have higher divergence than those from patients with IM and blood donors although no specific variants of the gene for GC were found. Comparison of LMP1 sequences from tumor tissue and cells of oropharyngeal washing specimens from the same patients with EBV-negative GC revealed the common LMP1 variant in 2 cases while they differed in 3 cases. The findings are an initial step in studying the role of EBV in the carcinogenesis of EBV-negative GC that is likely to be established by investigations on representative clinical material, by applying the up-to-date technologies.

To elucidate the role of some viral and cellular proteins in the occurrence and development of HERV-K-associated germ-cell tumors (GCT), reverse-transcription polymerase chain reaction using specific primers has been employed to study the transcription of the protein Rec HERV-K and the possible interaction of the protein Rec(cORF), that has transforming properties, and the cellular protein PLZF, that is a negative regulator of cell division, in human GCT tissues, in the testicular parenchyma adjacent to a tumor, and in the normal testicular tissues. It was shown that there was expression of Rec(cORF) of mRNA, rather than cellular PLZF in all malignant GCT tissues, this led to the conclusion that no interaction occured between the Rec HERV-K and PLZF proteins in the GCT cells. At the same time co-expression of Rec and PLZF protein was first revealed at the level of transcription in the testicular parenchyma adjacent to a tumor that exhibited carcinoma in situ cells. By taking into account that the protein Rec HERV-K has transforming activity and it is presumed to be Implicated in the development of GCT, the authors discuss a possible role in the Rec HERV-K/HTDV and cellular PLZF interaction in the pathogenesis of GST at the early stages of its genesis.

The correlation between DRB1, DQA1, and DQB1 genes of HLA class II, and the development of germ cell tumors (GCTs), as well as serological response to HERV-K proteins were investigated. Genomic DNA prepared from 99 GST patients was subjected to HLA typing by polymerase chain reaction (PCR) using the set of sequence specific primers (PCR-SSP). This set of primers made it possible to detect 14 specificities of DRB 1 locus, 12 alleles and groups of alleles of DQB 1 locus, and 8 alleles of DQA1 locus. Alongside with the definition of the occurrence of HLA markers in the total group of patients, the frequency of the occurrence of HLA-DR-DQ alleles was calculated in: 1) patients with different morphological forms of GSTs (seminomas and non-seminomas); 2) GCT patients producing or non-producing antibodies to Gag and/or Env HERV-K proteins. The comparison group consisted of 300 Moscow blood donors. The study did not reveal statistically significant differences in the frequency of the occurrence of DRB1, DQA1, and DQB1 alleles between the total group of GCT patients, its subgroup, and the control group. Thus, the data obtained demonstrated the absence of a strict correlation between the distribution of HLA class II alleles and GCT occurrence in the Russian population, as well as the ability of GCT patients to develop an antibody to HERV-K proteins, though more numerous observations are required to confirm this conclusion.

Human germ cell tumors (GCT) have been found to be closely associated with the expression of HERV-K/HTDV proviruses and most patients with GCT produce antibodies to the major HERV-K/HTDV Gag and Env proteins. The findings have shown a strong association of the level of HERV-K/HTDV antibodies with the clinical course of the disease and therapy success, which makes it possible to confirm the fact that viral protein antibodies may be used as an additional marker of GCT.

Transcription of HERV-K/HTDV proviruses in various morphological forms of GCTs and in normal testicular parenchyma and placenta was studied by RT-PCR with specific primers discriminating type 1 proviruses from type 2 ones. The results indicate that transcription of type 2 HERV-K/HTDV proviruses takes place and mRNA of protein cORF, coded for only by type 2 proviruses, is synthesized in all malignant germinogenic tumors. In normal testicular tissue and placenta type 1 HERV-K/HTDV proviruses are expressed. No expression of HERV-K/HTDV proviruses was detected in nongerminogenic testicular tumors. Since cORF protein possesses transforming activity, its possible role in the pathogenesis of GCTs is discussed. Generation of humoral immune response to structural HERV-K/HTDV proteins in various morphological forms of GCTs confirmed the possibility of using antibodies to structural HERV-K/HTDV proteins as additional markers of GCTs.

Associations of a new human herpesvirus type 8 (HHV-8) with different forms of Kaposi's sarcoma (KS) in Russia have been studied. Search for this virus genetic information has been carried out in biopsy specimens of benign and malignant tumors other than KS, and probable sites of HHV-8 latency in human body have been checked. HHV-8 sequences were detected by polymerase chain reaction (PCR). HHV-8 sequences were most often detected in idiopathic (80.6%), AIDS-associated (80%), and immunosuppressive (100%) KS. The results indicate a selective association of HHV-8 with KS. No probable sites of the virus latency were detected in peripheral blood cells of patients with KS and in the prostate of patients with chronic prostatitis. The only exception was the husband of a patient with KS: HHV-8 sequences were detected in his prostatic secretion by nested PCR.

Three HTLV-I-infected partially interleukin-2-dependent lymphoid cell lines were derived from a patient with T-cellular leukemia (ATL) from Georgia and a carrier of HTLV-I from Sakhalin. The strains cultured in the presence of 3-5% interleukin-2 were designated as NBK-1, NBK-2, and YE-1, respectively. Immunoblotting analysis showed typical HTLV-I proteins in them except NBK-2 which expressed nontypical proteins p40K and p28-29K. Unexpectedly, leukemic cell fraction ATL/NBK from a patient contained gag proteins p19 (CA), p24 (MA), Pr53, and unidentified protein p29. Southern blot analysis of primary leukemic cells NBK showed one full-length non-defective provirus with restriction sites Sacl in both LTRs. Limited restriction map of the provirus virtually did not differ from previously described HTLV-I prototypes. Although the mechanism of abnormal protein expression remains to be determined, this event can be explained by defective provirus formation in NBK-2 cell line during coculturing of leukemic cells with human umbilical cord blood lymphocytes.

Representatives of various population groups in Azerbaijan were tested for infection with human T-lymphotropic (HTLV-I and HTLV-II) and hepatotropic viruses (HCV and HBV). A total of 835 sera were studied by screening and specific tests for virus-specific antibodies and/or antigens. Thirty-five DNA specimens from peripheral blood lymphocytes were analyzed in the PCR for HTLV-I-specific sequences. No HTLV-I or HIV were detected, but two cases with integration of the HTLV-I LTR gene into cellular DNA genome were detected. A high rate of infection with hepatitis B and C was revealed. The level of anti-HCV was 8.7%, HBsAg 4.1%, and antiHBs 23.4%. Six cases with double HBV-HCV infection were detected. High values of ALT among HBV/HCV-seronegative subjects prompts their testing for other types of hepatitis viruses.

Seroepidemiological and molecular-biological screening of 1510 donor blood samples, collected from the residents of the town of Ashgabat (Turkmenistan), for lymphotropic virus of human T-cellular leukemia (HTLV) virus revealed one donor with a high level of immune response to a wide spectrum of viral proteins. Three donors were serologically assessed as dubious, for their sera contained antibodies to gag gene protein but no antibodies to env gene protein. Screening of family members of the donor infected with HTLV-1 revealed four more highly reactive carriers of HTLV-1 virus. The presence of proviral sequences of HTLV-1 in the lymphocyte DNA of infected donor and her relatives was confirmed by polymerase chain reaction and subsequent Southern-blot hybridization of specific amplification products. Proviral sequences of gag, pol, and LTR genes were detected in all the cases. Short-term culturing of peripheral blood lymphocytes of all seropositive subjects was associated with expression of HTLV-1 structural proteins. Analysis of the possible routes of transmission of HTLV-1 isolated in Turkmenistan permits us to hypothesize an Iranian origin of the isolated virus strain.

Twelve synthetic peptides corresponding to 9 immunodominant regions of structural proteins of human retroviruses HTLV-I, HIV-1, and HIV-2 were studied in enzyme-linked immunosorbent assay for cross reactivity with heterotypical for each peptide anti-retroviral antibodies. The search of amino acid homologies was carried using the special computer program followed by the correspondence analysis of the discovered homologies and immunodominant fragments. It was found that peptides 100-130 p19 gag HTLV-I, 376-392 gp21 env HTLV-I, 381-400 gp21 env HTLV-I, 306-328 gp120 env HIV-1, 495-516 gp120 env HIV-1, 584-612 gp41 env HIV-1, and 581-603 gp36 env HIV-2 have type-specific reactivity and also cross react with 3-54% human sera containing antibodies against heterotypical retroviruses. On the other hand, peptides 120-130 p19 gag HTLV-I, 176-201 gp46 env HTLV-I, 291-312 gp46 env HTLV-I, 330-363 p24 gag HIV-1, and 602-624 gp41 env HIV-1 have shown no cross reactive properties; they may be effectively used for type-specific and differential serodiagnosis of human retroviral infections.

The immunoreactivity of 25 synthetic peptides corresponding to amino acid fragments of the HTLV-I structural proteins p19 gag, gp46 and gp21 env were studied in enzyme linked immunosorbent assay using a serum panel of 70 reference positive specimens with anti-HTLV-I antibodies. The location of the synthetic peptides containing the B-cell epitopes of HTLV-I was established. Anti-HTLV-I antibodies effectively recognized these peptides. The significance of some amino acids for forming the HTLV-I antigenic determinants was estimated. The synthetic peptides with amino acid sequences 100-130 p19 gag and 176-201 gp46 env were found to have most immunoreactivity (90-99% recognition by sera of HTLV-I infected patients) and mimic the immunodominant B-cell epitopes of HTLV-I structural proteins.

The results of examinations for the presence of antibody to HTLV-I of 205 sera which were positive or indefinite (doubtful) with regard to HIV are presented. No evidence indicating simultaneous infection with HIV and HTLV-I viruses in 18 HIV-positive subjects was obtained. Antibodies to gag-proteins p19 and p28 HTLV-I were detected in one serum showing primary reactivity in screening for HIV antibodies. Problems of HIV and HTLV-I occurrence and sensitivity of screening test systems are discussed.

The first of case of adult T-cell prolymphocytic lymphosarcoma is reported which according to the natural course, cell composition of tumor, cell surface markers as well as expressed immune response to a wide spectrum of HTLV-1 gag an env encoded proteins can be classified as HTLV-associated adult T-cell leukemia. Diagnosis of the tumor alongside with identification of HTLV-1-infected individuals in the USSR emphasizes the need to stimulate research in HTLV-1-associated carcinogenesis in this country.

The results of serologic survey of 4118 residents of the USSR Far East from 16 to 82 years of age and 1037 blood donors for antibody to HTLV-I by the method of passive agglutination of gelatin particles coated with viral proteins are summarized. The portion of HTLV-1 seropositive subjects in the Khabarovsk Territory was 1.79% (25 out of 1391), in the Maritime Territory 2.2% (18 out of 801), in the Sakhalin Island 1.6% (26 out of 1557), and in Kamchatka 1.6% (6 out of 369). A discrete area of a higher number of positive cases was found among Nivkhi national group in the village of Nogliki in the Sakhalin Island: 6.4% (10 out of 155). In women, antibody to HTLV-1 was found twice as frequently as in men. Seropositives to HTLV-1 among blood donors in Moscow, the town of Komsomol'sk-na-Amure, and the town of Yuzhno-Sakhalinsk comprised 1.4%, 1.6%, and 5.45%, respectively. The occurrence of HTLV-1 infection among the normal population of the Far East and especially among blood donors attests to the expedience of wider seroepidemiological surveys of the population and especially donors for HTLV-I infection in other regions of the USSR as well.

Two immunological tests were used in testing of 808 blood serum samples from inhabitants of Sakhalin and of the city of Yuzhno-Kurilsk for antibodies against HTLV-1 etiologically associated with human T-cell leukemia. Antibodies to HTLV-1 were detected in 4.2% of Nivkhs, 1.2% of Oroks and 1.5% of Russians. The highest level of virus-carriers reaching 6.0% was detected in Nivkhs from the middle part of Sakhalin. The antibodies were detected more often in persons of old age and in women.

Sera from 867 donors were tested for antibodies to the virus of T-lymphocyte leukemia of adults (HTLV-I) in parallel by indirect immunofluorescence on acetone-fixed cells of HUT-102 culture producing HTLV-I and by agglutination test using a commercial set ("Serodia-ATLA", Japan). Twelve (1.38%) out of 867 sera were positive in the agglutination test and only 7 of them in immunofluorescence test. The specificity of the results was verified by absorption experiments. The activity of the sera in the agglutination test disappeared completely after their absorption with HUT-102 culture cells but did not change after absorption with LLU cells producing no HTLV-I despite a low percent of virus infection, donor blood control for HTLV-I infection becomes mandatory.

Antibodies to HTLV-1 were detected in sera from 1298 healthy adult persons living in the Far East. It is shown that virus infectivity of the Nigidalts was 8%, Nivkhs--2%, Udegeits--2.9%, Oroches--2.4%, Russians--0.9%. However, the incidence of acute leukemia in these regions is low. It is suggested that these regions are not endemic areas for HTLV-1-associated haemoblastoses.

Reproduction of the Mazurenko leukemia virus was studied in cell lines of different origin. Mongrel rat fibroblasts nonproductively transformed with variola vaccine virus proved to be the most adequate system for the virus replication. The leukemogenic virus reproduction in transformed rat cells was observed for 250 days.

The expression of 8 protooncogenes was examined in different types of murine leukemia induced by Mazurenko virus. C-myc-specific RNA (2, 3 kb and 1.8 kb) was revealed only in tissues of mice with thymomas (T-cell leukemias) but not with generalized leukemias. 1.4 kb Ha-ras RNA transcripts were observed in all RNA species from leukemic mice. The highest expression of the above oncogenes was noted in thymus and lymph nodes, in spleen and liver the expression was lower. Ki-ras, abl, fos, myb, erb and B-lym-specific RNA expression was not observed in any of the tissues tested. The expression of C-myc RNA is believed to be the result of C-myc activation due to provirus integration.