A human retrovirus was isolated from the peripheral blood of three American patients newly diagnosed with the acquired immunodeficiency syndrome (AIDS). In each case the major core viral protein (p25) was shown to be antigenically identical to that of the prototype lymphadenopathy-associated virus (LAV). Two of the viral isolates were derived from intravenous narcotics abusers, the first demonstration of LAV isolation from this risk group. Antibody to LAV was detected by an IgG enzyme-linked immunosorbent assay in the serum samples of these and 14 additional American patients with AIDS and in none of 12 hospital worker controls. These findings provide support for the etiologic association of LAV and AIDS.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Western blot technique in the serological evaluation of three LAV/HTLV III-infected Italian families.

In order to confirm suspected LAV/HTLV III infection, serological evaluation of patients is of utmost importance. ELISA is currently being employed on a large scale for screening, but like the immunofluorescence assay, it has a variable rate of possible non-specific positivity. On the other hand, the Western Blot (WB) technique can detect antibodies to different viral proteins. In this paper we are reporting the serological patterns of three LAV/HTLV III-infected families. In particular, their viral protein-specific antibody patterns are described. With the exception of one child, all the patients tested showed seropositivity in both ELISA and WB. In the one child mentioned above, ELISA and immunofluorescence positivity were due to non-specific binding. Two out of three children tested showed a close correlation between a severe clinical course and the absence of p25-specific IgM. In contrast, one child showing a switch from IgM to p25-specific IgG antibodies had a favorable clinical course. We observed a family in which vertical transmission of LAV/HTLV III from the mother to her neonate seems not to have happened; the child was seronegative and healthy at the age of one. At birth, this neonate had LAV/HTLV III-specific IgG corresponding to the mother's pattern, but it lacked viral-specific IgM. Its mother had transmitted the viral infection to her first child, who died of AIDS. Preliminary suggestions are made about the detection of different specific antibodies and clinical features; the utility of WB is emphasized.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Human T-lymphoblastoid cells selected for growth in serum-free medium provide new tools for study of HIV replication and cytopathogenicity.

Human T-lymphoblastoid cells H9, CEM and CEM-clone 5 were selected for growth in RPMI 1640 supplemented with transferrin 5 micrograms/ml, insulin 5 micrograms/ml and sodium selenite 5 ng/ml. After 40 days of adaptation to serum-free medium, these cells displayed growth, morphology, and expression of CD4 similar to serum-supplemented cultures. Infection of these cells with two strains of HIV-1 (LAV and NDK) and a strain of HIV-2 (ROD) was as efficient in serum-free as in serum-supplemented medium as demonstrated by reverse transcriptase activity in the culture supernatants of infected cells. Furthermore, HIV-induced cytopathogenicity was observed in serum-free cultures, demonstrating that both HIV infection and cytopathic effect did not require the presence of serum components. Electron microscopy showed that mature viral particles were produced from infected cells cultured in serum-free medium. Finally, the ability of monoclonal antibody OKT4 A to inhibit infection by HIV-1 LAV but not by HIV-1 NDK was the same with and without serum in the culture medium, demonstrating that both CD4-dependent and CD4-independent infections can occur in the total absence of serum. Human T-lymphoblastoid cells adapted for growth in serum-free medium provide therefore a complementary tool for the study of HIV infection and cytopathogenicity under defined conditions.

CD4 Antigens↗

PubMedDate not supplied

Anti-beta 2-microglobulin monoclonal antibodies mediate a delay in HIV1 cytopathic effect on MT4 cells.

We attempted to select monoclonal antibodies (mAb) which reacted with T-cell surface molecules and were able to interfere with the human immunodeficiency virus type 1 (HIV1) replicative cycle in the MT4 T-leukaemic cell line. In comparison with OKT4A, an anti-CD4 mAb, only one mAb, HC11.151.1, was found to significantly delay HIV-induced cytopathic effect on MT4 cells among the 15 mAb tested which reacted with MT4 cell surface antigens. Biochemical and immunological characterization of HC11.151.1 demonstrated its specificity for beta 2-microglobulin (beta 2m), the light chain of human leukocyte antigen (HLA) class I molecules. Other beta 2m-specific mAb were tested in order to assess whether this effect represented an intrinsic capacity of HC11.151.1 or whether it was a common feature shared by all anti-beta 2m mAb. Three (B1.1G6, B2.62.2 and BBM1) of the four anti-beta 2m mAb demonstrated the same protective effect, whereas C21.48A, which was devoid of a functional effect, was directed towards a beta 2m epitope involved in binding to the HLA class I heavy chain molecule. The physiological relevance of this observation is discussed.

Antibodies, Monoclonal↗

PubMedDate not supplied

Effects of thymus humoral factor gamma-2 (THF gamma 2) on lymphohaematopoietic progenitor cells: an in vitro study.

Thymus humoral factor gamma-2 (THF gamma 2), an immunomodulatory factor, was previously shown to exert a regulatory effect upon human haematopoietic development. In the present study, we were primarily interested in determining whether THF gamma 2 has an immunorestorative effect after HIV infection. Although no inhibition of viral production by T-cluster-forming cells and their mature progeny was observed, this thymus-derived compound prevented the dramatic decrease in CD4+ cells observed in cultures of immature T cells from normal bone marrow infected with HIV 1.

Antiviral Agents↗

PubMedDate not supplied

HIV-associated diseases: acute and regressive encephalopathy in a seropositive man.

We observed the development of acute encephalopathy in a healthy human-immunodeficiency-virus(HIV)-seropositive man. HIV was isolated from cerebrospinal fluid but not from peripheral blood. Signs and symptoms resolved quickly without treatment. This viral isolate could be propagated only in umbilical cord lymphocytes, but not in peripheral blood T lymphocytes or in continuous lymphoblastoid cell lines such as CEM. The absence of the virus in the patient's T lymphocytes or infectivity of the virus for T lymphocytes may explain the unusual presentation of HIV-associated encephalopathy without immunodeficiency in an asymptomatic carrier. Moreover, it raises the possibility that acute expression of HIV can be controlled by natural host defence mechanisms and that clinical manifestations may be reversible despite the fact that the patient remains seropositive.

AIDS Dementia Complex↗

PubMedDate not supplied

Use of monoclonal antibodies for the detection and quantitation of HIV1 core protein p25: comparative evaluation of in vitro HIV1 infection by immunofluorescence, antigen capture ELISA and reverse transcriptase assays.

A two-site enzyme linked immunosorbent assay (ELISA) was developed to detect and quantify the HIV1 core protein p25 in the cell-free supernatant from virus-infected CEM cell culture, and compared with other assays. The assay, based on a sandwich method, employs two monoclonal antibodies (mAb) directed against different epitopes on the p25 core protein of HIV1, one used for p25 antigen capture and the other as a biotinylated probe. This immunoassay is sensitive enough to detect as little as 30 pg/ml of recombinant p25, the range of sensitivity of commercial kits, and therefore compares favourably with the conventional reverse transcriptase assay. Moreover, several hundred assays can be monitored quite conveniently by this simple ELISA procedure, which represents a useful tool for detection of HIV1 replication in microculture systems and rapid screening of antiretroviral agents using the reference strain HIV1-BRU as a model system.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Differential HIV replication and HIV-induced interferon production in mononuclear phagocytes: relationship to cell maturation.

We have investigated the replication of human immunodeficiency virus (HIV) and HIV-induced interferon (IFN) production in human mononuclear phagocytes at 2 different stages of in vitro maturation. Blood monocytes and monocyte-derived macrophages from 6 healthy, HIV-seronegative donors were challenged with HIV1IIIB and HIV2ROD. Freshly separated monocytes produced IFN when inoculated with both HIV types. In these cultures, an inverse correlation was observed between the amount of IFN production and the rate of HIV replication. In contrast to the monocytes, 5-day-old monocyte-derived macrophages did not produce IFN when challenged with HIV, but a significant replication of HIV1IIIB and HIV2ROD was found in all cultures.

Acquired Immunodeficiency Syndrome↗