Prevalence of antibodies to lymphadenopathy-associated retrovirus in African patients with AIDS.

The presence of antibodies to lymphadenopathy-associated retrovirus (LAV) was determined by a radioimmunoprecipitation assay and by an enzyme-linked immunosorbent solid assay of sera from Zairian patients with the acquired immune deficiency syndrome (AIDS) in 1983. Thirty-five of 37 patients (94 percent) and 32 of 36 patients (88 percent), respectively, were seropositive by the two tests. In a control group of 26 patients, six (23 percent) showed positive results in these tests. Of these six control patients, five had clinically demonstrable infectious diseases and a low ratio of T4 to T8 lymphocytes. In addition, sera collected from a control group of Zairian mothers in 1980 were positive for LAV in 5 of 100 cases. Other serologic data suggest that LAV was present as early as 1977 in Zaire.

Adaptation of lymphadenopathy associated virus (LAV) to replication in EBV-transformed B lymphoblastoid cell lines.

A strain of lymphadenopathy associated retrovirus ( LAV ) passaged in vitro was used to infect a lymphoblastoid cell line obtained by transformation with Epstein-Barr virus of B lymphocytes from a healthy donor. The virus produced from this line (B- LAV ) was also able to grow at a high rate in some other lymphoblastoid lines and in a Burkitt lymphoma line. This adapted strain retained the biochemical, ultrastructural, and antigenic characteristics of the original strain, as well as its tropism for normal T4+ lymphocytes. It is thus possible to grow LAV in large quantities that can be used for the preparation of diagnostic reagents. The interaction between such a human retrovirus and Epstein-Barr virus, a DNA virus, may have some implication for the pathology of the acquired immunodeficiency syndrome and related diseases.

Isolation of a new human retrovirus from West African patients with AIDS.

The etiological agent of AIDS, LAV/HTLV-III, is common in Central Africa but is not endemic in other areas of that continent. A novel human retrovirus, distinct from LAV/HTLV-III, has now been isolated from two AIDS patients from West Africa. Partial characterization of this virus revealed that it has biological and morphological properties very similar to LAV but that it differs in some of its antigenic components. Although the core antigens may share some common epitopes, the West African AIDS retrovirus and LAV differ substantially in their envelope glycoproteins. The envelope antigen of the West African virus can be recognized by serum from a macaque with simian AIDS infected by the simian retrovirus termed STLV-IIImac, suggesting that the West African AIDS virus may be more closely related to this simian virus than to LAV. Hybridization experiments with LAV subgenomic probes further established that this new retrovirus, here referred to as LAV-II, is distantly related to LAV and distinct from STLV-IIImac.

Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS).

A retrovirus belonging to the family of recently discovered human T-cell leukemia viruses (HTLV), but clearly distinct from each previous isolate, has been isolated from a Caucasian patient with signs and symptoms that often precede the acquired immune deficiency syndrome (AIDS). This virus is a typical type-C RNA tumor virus, buds from the cell membrane, prefers magnesium for reverse transcriptase activity, and has an internal antigen (p25) similar to HTLV p24. Antibodies from serum of this patient react with proteins from viruses of the HTLV-I subgroup, but type-specific antisera to HTLV-I do not precipitate proteins of the new isolate. The virus from this patient has been transmitted into cord blood lymphocytes, and the virus produced by these cells is similar to the original isolate. From these studies it is concluded that this virus as well as the previous HTLV isolates belong to a general family of T-lymphotropic retroviruses that are horizontally transmitted in humans and may be involved in several pathological syndromes, including AIDS.

Autoantibodies typical of non-organ-specific autoimmune diseases in HIV-seropositive patients.

OBJECTIVE: To analyse serological aspects of systemic autoimmunity in HIV-1-seropositive patients and in individuals at risk for AIDS. DESIGN AND METHODS: The reactivity of antibodies in the serum of 100 HIV-1-seropositive patients was investigated by enzyme-linked immunosorbent assay (ELISA) using a series of antigens known to be recognized by antibodies from patients with multisystemic autoimmune diseases, such as systemic lupus erythematosus, mixed-connective tissue disease and Sjögren's syndrome. RESULTS: High levels of immunoglobulin G (IgG) antibodies reacting with double-stranded DNA (dsDNA), synthetic peptides of ubiquitinated histone H2A, Sm-D antigen, U1-A RNP antigen and 60 kD SSA/Ro antigen were found in 44-95% of HIV-infected patients. Among histone antibodies, the most frequent reactions were towards the carboxy-terminal region of histone H1 and to histone H2B and its amino-terminal domain 1-25. Eight HIV-1-seropositive patients at different stages of disease according to the Centers for Disease Control classification were also studied. In most cases, no obvious fluctuations were observed over several years. Antibodies were found early, and their specificity and apparent level of activity remained relatively constant. There was no evidence of such an autoimmune response in the serum of high-risk homosexual seronegative men. CONCLUSIONS: Although the aetiology of AIDS is known, in general the aetiology of multisystemic autoimmune diseases remains to be determined, and the sequence of events taking place remains obscure in both cases. It is possible that the large spectrum of antibodies found in HIV-infected patients reflects a specific stimulation of B-cells by nuclear antigens released by apoptosis during an early stage of disease.

HIV-2 antisera cross-neutralize HIV-1.

The neutralization properties of three independent HIV-2 isolates were examined in comparison with four diverse HIV-1 strains. Human sera containing antibodies specific to HIV-2 can cross-neutralize HIV-1. By contrast, HIV-1 sera are group-specific and have no neutralizing effect on HIV-2. Therefore, HIV-2 antigens may be important components for the development of broadly cross-protective AIDS vaccines.

A study of seroprevalence of HIV-1 and HIV-2 in six provinces of People's Republic of Angola: clues to the spread of HIV infection.

A seroepidemiological study was carried out to determine the distribution of the human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2) in the People's Republic of Angola, where HIV-2 existence was previously unknown and HIV-1 seropositivity was only reported to be present in Luanda and Cabinda. A total of 1,695 serum samples were obtained from healthy persons (control group) and from a group of patients in the provinces of Zaire (13), Lunda-Norte (L.N.) (749), Luanda (556), Huambo (154), Kuando-Kubango (K.-K.) (49), and Namibe (119). All samples were tested for HIV-1 and HIV-2 antibodies by enzyme-linked immunosorbent assay and an indirect immunofluorescence assay using MOLT-T4 cells. Positive samples were confirmed by the Western-blot technique. Sera giving cross reactivity at the level of HIV-1 and HIV-2 large glycoproteins were further tested by radioimmunoprecipitation assay and by reactivity against a peptide corresponding to the dominant epitope of the transmembrane protein. The overall seroprevalance was 14.2%, with significantly higher values in the patient group [19.4% (HIV-1 = 8.8%; HIV-2 = 8.4%; HIV-1 + HIV-2 = 2.2%)] than the control group [9.3% (HIV-1 = 3.3%; HIV-2 = 5.3%; HIV-1 + HIV-2 = 0.7%)]. HIV-2 as well as HIV-1 infection is actually present in Angola in all studied provinces. Higher seroprevalence was seen in the provinces of Zaire, Lunda Norte, and Huambo. People displacements, mainly as a consequence of the war, certainly play an important role in spreading HIV infection from the northern frontier areas of the country to the central and southern regions.

Antibodies to the nef protein and to nef peptides in HIV-1-infected seronegative individuals.

The silent period that follows infection by the human immunodeficiency virus (HIV-1) and precedes seroconversion remains a problem for the screening of blood supply, and knowledge about the mechanism involved in the maintenance of latency is only fragmentary. Using purified nef recombinant protein and six synthetic nef peptides, antibodies to the product of an HIV-1 regulatory gene, the negative regulatory factor (nef) involved in maintenance of proviral latency, were detected by Western blot and radioimmunoassay techniques in HIV-1-seronegative, viral antigen-negative, and virus culture-negative individuals at risk for HIV infection. This antibody response to nef was correlated in eight individuals with the detection of HIV-1 proviral DNA by oligonucleotide hybridization, following enzymatic amplification of HIV DNA in peripheral blood mononuclear cells. Such latent HIV infections have now been followed for up to 6 or 10 months in five individuals. In addition, retrospective and prospective analysis of HIV-1-seropositive individuals have shown (1) antibodies to nef preceding seroconversion, and (2) the persistence of antibodies to nef and of HIV-1 proviral DNA in a case of spontaneous complete HIV-1 seronegativation. Since DNA amplification cannot be currently considered for routine use, screening for anti-nef antibodies followed by confirmation by DNA amplification could represent a basis for new diagnostic strategies. Beyond their diagnostic implications, these findings, suggesting that regulatory genes of the HIV-1 provirus can be expressed prior to the initiation of virion synthesis, may also be applicable in the design of alternative vaccines against the acquired immunodeficiency syndrome.

Gag-specific cytotoxic responses to HIV type 1 are associated with a decreased risk of progression to AIDS-related complex or AIDS.

The duration of human immunodeficiency virus (HIV-1) infection prior to the development of AIDS is variable, and for most patients the exact time of infection is not known. A group of 38 HIV-1-infected subjects was tested while asymptomatic for comparative cytotoxic lymphocyte responses to the Gag and envelope antigens of HIV-1. Twenty of the 38 patients had no detectable primary cytotoxic T lymphocyte (CTL) response to Gag, and this was associated with a relative risk of 1.89 for progression to ARC or AIDS during the subsequent 3 to 40 months of observation when compared with patients who had Gag-specific CTL activity at the beginning of the observation period. In contrast, no significant association was observed between envelope-specific cytotoxic activity and disease progression. Other patient characteristics, including CD4+ T lymphocyte counts and antibody levels to the p24gag protein, measured at the start of observation, did not correlate with disease progression during the observation period. This suggests that the anti-Gag CTL response may be protective during HIV-1 infection.

[Inflammatory arthropathies in patients with human immunodeficiency virus infection]. / Arthropathies inflammatoires chez des malades infectés par le virus de l'immunodéficience humaine.

Articular manifestations were observed in 10 patients (8 men, 2 women, aged from 23 to 46 years) with human immunodeficiency virus (HIV) infection. All men were homosexuals, except for an intravenous drug addict. One woman was a native of Gabon and the other had multiple transfusions. The joint diseases were of the polyarthritis and acute oligoarthritis types, affecting mainly the knees and ankles but also the wrist and fingers; the spine was involved in one case. The synovial fluid present in 4 patients contained 5,000 to 27,000 cells per cubic millimeter, with a strong predominance of polymorphonuclears. In 3 cases, infective viral particles were found in the fluid with anti-HIV antibodies. In 2 patients biopsy of the synovial membrane provided evidence of non-specific subacute synovitis. All X-ray films, including those of the sacro-iliac joint, were and remained normal. The course of the joint disease was acute and regressive in 5 cases, chronic and prolonged in the remaining 5 cases. In 5 patients the arthropathies were the first clinical manifestations of the HIV infection. Three patients who had stage IV C AIDS died; the others were in stages II (5), III (1) or IV E (1) and did not progress to a more severe stage. This study shows that various types of inflammatory arthritis may occur in HIV positive patients. In most cases the arthritis is reactive, but certain data suggest that it may be directly related to the virus in some patients.

[Increase, in extracts of cancerous or transformed cells, of protein kinase activity phosphorylating tyrosine]. / Augmentation, dans des extraits de cellules cancéreuses ou transformées, de l'activité d'une protéine-kinase phosphorylant la tyrosine.

A protein kinase activity which phosphorylates tyrosine in the presence of Mn++ ions has been detected among different protein kinase activities in a postnuclear cell fraction sedimenting mostly at 12000 X g. The proportion of phosphotyrosine relative to phosphoserine and phosphothreonine is at a low level in normal embryonic cultured cells and is increased several fold in various types of cells either malignant or transformed in vitro. This proportion which may reach up to 8% is in the same range as that found in extracts of avian cells transformed by Rous sarcoma virus, where the viral kinase P60 src is expressed. In two ascitic tumour cells the tyrosine kinase activity seems to be associated with the mitochondrial fraction.

Detection of natural autoantibodies in the serum of anti-HIV-positive individuals.

Twenty-six sera containing anti-HIV antibodies from individuals with AIDS, AIDS-related complex, lymphadenopathy syndrome, or from seropositive individuals without clinical symptoms, were tested for the presence of natural autoantibodies (NAb) to actin, DNA, tubulin, thyroglobulin, albumin, myosin and TNP-BSA. Sera from 22 seronegative individuals at high risk for HIV infection were also examined. NAb titres to all these antigens were found to be elevated in both groups as compared to the titres in pooled normal human sera. The most prevalent NAb were those of the IgG class directed against TNP found in high titre in seropositive individuals. On the basis of the above results, sera from 50 anti-HIV-positive and 67 anti-HIV-negative individuals were tested for IgG antibody activity against a panel of protein antigens with different degrees of TNP substitution. The greater the TNP substitution, the higher the titres of IgG antibodies detected in anti-HIV-positive sera. Antibody titres in seronegative individuals at high risk for HIV infection were independent of the degree of TNP substitution. In almost all cases, the highest titres of IgG anti-TNP antibodies were found in anti-HIV-positive sera from individuals with clinical manifestations.

Association of tyrosine protein kinase activity with mitochondria in human fibroblasts.

A tyrosine protein kinase activity has been detected in the mitochondrial fraction purified from human fibroblasts. By enzymatic and sedimentation analysis this activity appeared to be localized in the mitochondrial outer membrane. Mitochondrial tyrosine phosphorylation was strictly dependent on the presence of Mn2+ ions. An inverse relationship between cell proliferation and mitochondrial protein phosphorylation on tyrosine residues has been found: a marked increase in the mitochondrial tyrosine kinase activity occurred when a significant reduction in the growth rate followed serum step-down. In mitochondria purified from resting cells, a protein band with apparent molecular weight of 50 kd appeared to be phosphorylated on tyrosine.

Identification and characterization of tyrosine kinase activity associated with mitochondrial outer membrane in sarcoma 180 cells.

Tyrosine protein kinase activity has been detected in the mitochondrial fraction purified from sarcoma 180 tumor cells. Following hypotonic disruption of mitochondria, tyrosine kinase activity appeared to cosediment with monamine oxidase, marker enzyme of mitochondrial outer membrane; meanwhile, serine and threonine kinases were found to be associated with the inner membrane and matrix of mitochondria. Mitochondrial tyrosine kinase(s) showed thermosensitivity and Mn2+ dependence, useful properties for its characterization and separation from tyrosine kinases associated with other particulate fraction and from serine and threonine kinases associated with mitochondria. Following in vitro incubation of mitochondria with labelled ATP as substrate and analysis by PAGE, a complex pattern of phosphotyrosine containing proteins with a major band of 50-55 kilodaltons resulted.

Characterization of 69- and 100-kDa forms of 2-5A-synthetase from interferon-treated human cells.

The existence of distinct 69- and 100-kDa forms of 2-5A-synthetase in addition to the smaller (40 and 46 kDa) forms has recently been established. Using specific monoclonal antibodies we investigated the induction, synthesis, and activity of 69- and 100-kDa 2',5'-oligoadenylate (2-5A) synthetases in interferon-treated human Daudi cells. Although induction of these synthetases is detectable in cells treated with as little as 1-5 units/ml of human alpha-interferon, higher concentrations are required for maximum synthesis of the 100 kDa than the 69-kDa protein. At 5 units/ml of interferon, enhanced synthesis of both proteins is detectable at 4 h with maximum synthesis occurring between 8 to 12 and 12 to 16 h for 69- and 100-kDa 2-5A-synthetases, respectively. At 24 h after addition of interferon, synthesis of these synthetases declines due to a decrease of active interferon in the culture medium. The synthesis of both synthetases is blocked by actinomycin D, and the half-life of these proteins is estimated to be 8 h. The activities of immunoaffinity purified 69- and 100-kDa synthetases are dependent on double-stranded (ds)RNA but show different requirements for optimum concentration of dsRNA and pH of the reaction. The apparent Km of 69- and 100-kDa synthetases for ATP is 1.7 X 10(-3) M and 3.6 X 10(-3) M, respectively. At optimum conditions for the activity of these enzymes, the pattern of 2',5'-linked oligoadenylates synthesized are different, the 69-kDa protein synthesizing higher oligomers than the 100-kDa species. Taken together, these results indicate that the 69- and 100-kDa 2-5A-synthetases are distinct proteins each with specific characteristics of induction and enzymatic activity.

Idiotypic expression of anti-gp120 antibodies in unrelated human immunodeficiency virus-infected individuals.

Although it is recognized that human immunodeficiency virus (HIV) env genes exhibit a high degree of variability, little is known about the molecular heterogeneity of gp120-specific antibodies in infected individuals. As a first step to approach this issue, we investigated the idiotypic relatedness of anti-gp120 antibodies present in the serum of HIV-infected individuals. Idiotypic determinants (idiotopes) are fingerprints of the variable region of the antibody molecule and, as such, they represent unique probes with which to explore the diversity of the immune response. We isolated IgG anti-gp120 antibodies from the serum of a seropositive asymptomatic individual by affinity chromatography. The purified antibodies were shown to bind gp120 and gp160 by ELISA, Western blotting and radio-immunoprecipitation. They also recognized HIV-infected human T cells as detected by immunofluorescence. Anti-idiotypic reagents were generated against this gp120 idiotype, and one of them was used to study anti-gp120 idiotypic diversity in a panel of 65 sera drawn from AIDS and AIDS-related complex patients, and from HIV seropositive asymptomatic individuals. Sixty normal human sera were used as negative controls. We found no evidence for common idiotopes on anti-gp120 antibodies of unrelated individuals. In contrast, we also noticed that the idiotypic profile expressed sequentially at two different intervals in a persistently infected individual showed little variation. Finally, when the diversity of murine anti-gp120 antibodies with a monoclonal anti-idiotype was analysed, no evidence of cross-reactive idiotopes in the murine system was found.