Retroviral antibodies in Indians

Zoonotic viruses associated with illegally imported wildlife products

The global trade in wildlife has historically contributed to the emergence and spread of infectious diseases. The United States is the world's largest importer of wildlife and wildlife products, yet minimal pathogen surveillance has precluded assessment of the health risks posed by this practice. This report details the findings of a pilot project to establish surveillance methodology for zoonotic agents in confiscated wildlife products. Initial findings from samples collected at several international airports identified parts originating from nonhuman primate (NHP) and rodent species, including baboon, chimpanzee, mangabey, guenon, green monkey, cane rat and rat. Pathogen screening identified retroviruses (simian foamy virus) and/or herpesviruses (cytomegalovirus and lymphocryptovirus) in the NHP samples. These results are the first demonstration that illegal bushmeat importation into the United States could act as a conduit for pathogen spread, and suggest that implementation of disease surveillance of the wildlife trade will help facilitate prevention of disease emergence.

An updated review of simian betaretrovirus (SRV) in macaque hosts

This review is an updated summary of nearly 30 years of SRV history and provides new and critical findings of original research accomplished in the last 5 years including, but not limited to, the pathogenetic mechanisms underlying the origin of hematopoietic abnormalities observed in infected hosts and proposed new SRV serotypes. Despite major advances in the understanding and control of SRV disease, much more remains to be learned and SRV continues to be an exciting and attractive primate model for comparative studies of the mechanisms of retroviral immunosuppression.

Human infection with foamy viruses

Virtually all nonhuman primate species investigated thus far including prosimians, New World and Old World monkeys and apes all harbor distinct and species-specific clades of simian foamy virus (SFV). However, evidence supporting the existence of a human-specific foamy virus (FV) is not yet available. Early reports describing widespread infection of healthy and sick humans with FV could not be confirmed. In contrast, all FV infections documented in humans are of zoonotic origin and are identified in persons occupationally exposed to nonhuman primates. The introduction of SFV into humans raises several public health questions regarding disease outcomes and potential for human-to-human transmissibility. The available data from a very limited number of SFV-infected humans suggest that these infections are nonpathogenic and are not easily transmissible. Additional studies are needed to better define the prevalence and natural history of SFV in humans.

Type D retrovirus markers in healthy Africans from Guinea

Sixteen matching sera and DNA samples from healthy African blood donors living in rural areas of Guinea were analysed for the presence of type D retrovirus markers. Screening for the antibodies against structural proteins of Mason-Pfizer monkey virus (M-PMV) was carried out by Western blot with a purified M-PMV as an antigen. Eight out of 16 sera samples were found to contain antibodies against at least two gag gene-coded proteins, and three of these were weakly positive against env gene-coded protein. Using PCR amplification and Southern hybridization, we detected M-PMV-like gag sequences in 11 out of 16 samples and env-related sequences in 8 out of 16 samples. Six DNAs were found to contain both M-PMV gag- and env-related sequences. Restriction endonuclease analysis of the PCR-amplified gag sequences from two individuals and direct DNA sequencing analysis of the amplimers confirmed their M-PMV-like origin. Detection of antibodies and M-PMV-related sequences in blood donors from Guinea, but not in French or Algerian blood donors, indicated exogenous SRV infection in humans from certain geographic areas of Western Africa.

Markers of type D retroviruses in children with Burkitt's-type lymphoma

Antibodies to gag-coded proteins of type D retroviruses have been detected in children with lymphadenopathy [1]. We tested 41 HIV noninfected children with lymphoproliferative diseases (27 cases of Burkitt's-type lymphoma, six cases of Hodgkin's disease, four cases of T-cell lymphoma, three cases of lymphoblastic lymphoma and one case of large-cell anaplastic lymphoma) for the presence of type D retroviral serological and genetical markers. Twenty-five healthy donors were tested as a control. DNA samples from peripheral blood lymphocytes were analyzed by the polymerase chain reaction (PCR) and Southern blotting for the presence of type D retroviral related sequences. MPMV pro-pol specific sequences have been detected in 18 out of 27 children with Burkitt's-type lymphoma. By means of Western blotting, six patients positive in PCR/Southern blotting analysis were also found to contain Mason-Pfizer monkey virus (MPMV) specific antibodies, in their sera. All children with other lymphoproliferative diseases as well as healthy donors were negative in PCR/Southern blotting and Western blotting analysis. These data suggest the possible association of type D retroviral markers with Burkitt's-type lymphoma of children.

Absence of association between human spumaretrovirus and Graves' disease

Graves' disease (GD) is an autoimmune thyroid disease. The etiology of GD is still not clear. Both genetic and environmental factors, such as infectious agents, are believed to be involved in its pathogenesis. Recent findings suggest a role for human spumaretrovirus (HSRV) in the pathogenesis of GD. To test this hypothesis, we looked for the HSRV gag region sequence in DNA extracted from the peripheral blood leukocytes and thyroid tissue of patients with GD, and controls. Genomic DNA was subjected to a highly sensitive nested polymerase chain reaction, followed by dot-blot hybridization with an internal probe. HSRV gag region DNA fragments were detected in the peripheral blood leukocytes of patients with GD and controls to a similar extent; 5.3% (2/38) of Caucasian patients with GD, 4.7% (2/43) of Caucasian controls, 4.7% (2/43) of African-American patients with GD, and 6.5% of (3/46) African-American controls. Similar values were obtained for the samples of thyroid tissues; 5.5% (1/18) of Caucasian patients with GD and 5.0% (1/20) of controls. The differences in all these comparisons were not statistically significant. These results do not support a role for HSRV in the pathogenesis of GD.

Molecular characterization of human immunodeficiency virus type 1 isolates from Venezuela

Eight HIV-1 isolates from Venezuela have been characterized by nucleotide sequencing of the entire reverse transcriptase (RT)- and surface glycoprotein (gp 120)-coding regions. Average mutant frequencies were 2.5 x 10(-2) substitutions per nucleotide (s/nt) for the RT-coding region, and 10 x 10(-2) or 6.8 x 10(-2) s/nt for the gp120-coding region, depending on whether gaps introduced for optimal alignment were or were not, respectively, considered in the calculations. Phylogenetic trees were derived by maximum-likelihood, neighbor-joining, and maximum parsimony methods. In the trees derived from both RT- and gp120-coding regions, Venezuelan isolates cluster with subtype B viruses. However, the relative position of some of the isolates is considerably different in the two trees. Unique V3 loop amino acid sequences, not represented in the current database, have been identified among the Venezuelan isolates. In addition to representing the first molecular characterization of HIV-1 from Venezuela, the extensive genetic heterogeneity observed reinforces the interest in characterizing additional HIV-1 isolates worldwide for adequate vaccine design.

Identification of human type D retrovirus as a contaminant in a neuroblastoma cell line

In this report we describe a type D virus isolated from a human neuroblastoma cell line (Paju). The viral RNA was isolated, partially molecularly cloned and sequenced. Our clones were shown to be identical to a human D-type retrovirus previously isolated from a human lymphoblastoid cell line. However, we obtained no evidence for the virus in earlier passage of the Paju cell line and therefore we must consider this isolate a laboratory contamination. contamination.

Insertion of SMRV-H viral DNA at the c-myc gene locus of a BL cell line and presence in established cell lines

Mutation of the c-myc gene locus has occurred during in vitro culture of the Burkitt lymphoma cell line Namalwa. Gene cloning and sequencing of this c-myc gene locus has revealed the insertion of incomplete copies of the Squirrel Monkey Retrovirus-Human (SMRV-H) proviral genome. Insertions of the SMRV-H genome were seen in all Namalwa cell lines tested, with multiple insertions being seen in some sublines. Viral particles with the morphology of type-D retrovirus, budding from these cells, were seen by transmission EM. New insertions of the genome were produced spontaneously in these cells. The origins of the type-D retrovirus and its implications for workers in the field are discussed.

Human spumavirus antibodies in sera from African patients

Serum samples collected from patients with a wide variety of diseases from African and other countries were tested for antibodies to the human spumaretrovirus (HSRV). A spumaviral env-specific ELISA was employed as screening test. Out of 3020 human sera screened, 106 were found to be positive (3.2%). While the majority of patients' sera from Europe (1581) were negative, 26 were positive (1.6%). Sera from healthy adult blood donors (609), from patients with multiple sclerosis (48), Graves' disease (45), and chronic fatigue syndrome (41) were negative or showed a very low prevalence for spumaviral env antibodies. A higher percentage of seropositives (6.3%) were found among 1338 African patients from Tanzania, Kenya, and Gabon. Out of 1180 patients from Tanzania, 708 suffered from tumors, 75 from AIDS, and 128 had gynecological problems; 51 of the Tanzanian patients were HSRV seropositive (4.3%). A particularly high percentage of 16.6% seropositives were identified among nasopharyngeal carcinoma patients (NPC) from Kenya and Tanzania consistent with results reported 10 years ago. However, 20 nasopharyngeal carcinoma patients from Malaysia were HSRV-seronegative. In selected cases, sera from seropositive individuals were reacted with proteins from HSRV-infected cells in vitro. HSRV env- and gag-specific antibodies were specifically detected by these sera in Western blots. The results indicate spumavirus infections in human patients with various diseases at a relatively low prevalence worldwide; in African patients, however, the prevalence of spumavirus infections is markedly higher.

Human retroviruses

It was only in 1980 that the first human retrovirus, HTLV-1, was isolated. Since then, HTLV-2, HIV-1 and HIV-2 have been identified. All four viruses are transmitted with varying efficiency sexually, vertically from mother to infant, and through blood by transfusion or contamination. HTLV-1 is endemic in populations in south-west Japan, Taiwan, sub-Saharan Africa, the Caribbean, southern USA, central and south America, Australia, Papua New Guinea, Solomon Islands and western Asia. There is now epidemic spread amongst IVDUs in north and south America and southern Europe. HTLV-1 is the aetiological agent of adult T-cell leukaemia/lymphoma (ATL) and tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM). Other associations which may be causative are with polymyositis, infective dermatitis, gastrointestinal malignant lymphoma and chronic lymphatic leukaemia. ATL appears to be due to malignant transformation of HTLV-1 infected cells, and TSP/HAM to chronic activation of these cells. The epidemiology of HTLV-2 is being separated only recently from HTLV-1 through the application of PCR. It has a low level of endemicity in populations of central Africa, and central and south America. It is being spread epidemically amongst IVDUs in north America and southern Europe. Its association with any pathology in man remains uncertain. HIV-1 is epidemic and spreading rapidly throughout the world. In areas where homosexual contact was the predominant mode of transmission, heterosexual spread is becoming increasingly important. The areas where heterosexual contact is the predominant mode of transmission include the worst affected populations in the world, for example sub-Saharan Africa and some of the Caribbean. There have been recent and explosive increases of HIV-1 seroprevalence in IVDUs and female prostitutes in Asia, especially Thailand and India. Of the diverse pathology following infection, only the haematological consequences are reviewed in detail: these include anaemia, leucopenia, thrombocytopenia, disorders of coagulation and lymphomas. HIV-2, compared to HIV-1, is less infectious and causes less immunosuppression with more slowly progressive disease. It is prevalent in west Africa, but is spreading, albeit slowly, far beyond.

Isolation of a type D retrovirus from B-cell lymphomas of a patient with AIDS

An atypical syncytial variant of a high-grade Burkitt's-type B-cell lymphoma from a patient with AIDS who was seropositive for human immunodeficiency virus type 1 was studied. A productive type D retrovirus infection was identified in early-passage cell lines derived from two lymphomas from this patient. Nucleotide and amino acid sequence analysis as well as immunologic reactivity indicated that the isolated virus was highly related to Mason-Pfizer monkey virus (MPMV). MPMV is an immunosuppressive type D retrovirus that causes an AIDS-like syndrome in rhesus macaques. Amplification of DNA from the patient's diagnostic bone marrow biopsy specimen by polymerase chain reaction generated the appropriate MPMV-specific fragments and indicated that the patient was infected with the MPMV-like retrovirus. In addition, the patient's serum contained antibodies which recognized type D viral env proteins (gp70 and gp20) and gag proteins (p27 and p14). Although there have been reports of human cell lines infected with type D retroviruses and of type D-reactive human sera, this is the first evidence of a type D retrovirus infection in a human confirmed by virus isolation, serum reactivity, and viral DNA identification in tumor tissue.