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We have probed the structure of the C4 and V3 domains of human immunodeficiency virus type 1 gp120 by immunochemical techniques. Monoclonal antibodies (MAbs) recognizing an exposed gp120 sequence, (E/K)VGKAMYAPP, in C4 were differentially sensitive to denaturation of gp120, implying a conformational component to some of the epitopes. The MAbs recognizing conformation-sensitive C4 structures failed to bind to a gp120 mutant with an alteration in the sequence of the V3 loop, and their binding to gp120 was inhibited by both V3 and C4 MAbs. This implies an interaction between the V3 and C4 regions of gp120, which is supported by the observation that the binding of some MAbs to the V3 loop was often enhanced by amino acid changes in an around the C4 region.  相似文献
2.
Simian immunodeficiency virus from African green monkeys.   总被引:24,自引:14,他引:10       下载免费PDF全文
Simian immunodeficiency virus (SIV) was isolated from the total peripheral blood mononuclear cell population and the monocyte-macrophage adherent cell population of three seropositive green monkeys originating from Kenya. SIV from these African green monkeys (SIVagm) was isolated and continuously produced with the MOLT-4 clone 8 (M4C18) cell line but not with a variety of other cells including HUT-78, H9, CEM, MT-4, U937, and uncloned MOLT-4 cells. Once isolated, these SIVagm isolates were found to replicate efficiently in M4C18, SupT1, MT-4, U937, and Jurkat-T cells but much less efficiently if at all in HUT-78, H9, CEM, and MOLT-4 cells. The range of CD4+ cells fully permissive for replication of these SIVagm isolates thus differs markedly from that of previous SIV isolates from macaques (SIVmac). These SIVagm isolates had a morphogenesis and morphology like that of human immunodeficiency virus (HIV) and other SIV isolates. Antigens of SIVagm and SIVmac cross-reacted by comparative enzyme-linked immunosorbent assay only with reduced efficiency, and optimal results were obtained when homologous antibody and antigen were used. Western blotting (immunoblotting) of purified preparations of SIVagm isolate 385 (SIVagm385) revealed major viral proteins of 120, 27, and 16 kilodaltons (kDa). The presumed major core protein of 27 kDa cross-reacted antigenically with the corresponding proteins of SIVmac (28 kDa) and HIV-1 (24 kDa) by Western blotting. Hirt supernatant replicative-intermediate DNA prepared from cells freshly infected with SIVagm hybridized to SIVmac and HIV-2 DNA probes. Detection of cross-hybridizing DNA sequences, however, required very low stringency, and the restriction endonuclease fragmentation patterns of SIVagm were not similar to those of SIVmac and HIV-2. The nucleotide sequence of a portion of the pol gene of SIVagm385 revealed amino acid identities of 65% with SIVmac142, 64% with HIV-2ROD, and 56% with HIV-1BRU; SIVagm385 is thus related to but distinct from previously described primate lentiviruses SIVmac, HIV-1, and HIV-2. Precise information on the genetic makeup of these and other SIV isolates will possibly lead to better understanding of the history and evolution of these viruses and may provide insight into the origin of viruses that cause acquired immunodeficiency syndrome in humans.  相似文献
3.
Six different anti-HIV envelope antibodies and one irrelevant control antibody were coupled to ricin A chain and tested for their efficacy in inhibiting HIV tissue culture infections. The anti-HIV antibodies consisted of five monoclonals, three of murine and two of human origin, and one polyclonal preparation prepared by affinity purifying pooled serum antibodies from HIV-infected humans on rgp160. The binding specificity of the antibodies was defined by ELISA by using recombinant envelope proteins and synthetic peptides, and by flow cytometry on HIV-infected cells. The in vitro efficacy of the antibodies was tested by the abilities of the immunotoxins to inhibit protein synthesis in persistently infected cell lines and by their abilities to inhibit HIV production during both acute and persistent infection as measured with an HIV-specific focal immunoassay. The immunotoxins were tested against a panel of distinctly different HIV isolates. The results indicate the following: 1) A mAb to the immunodominant neutralizing loop was highly effective against homologous strains of HIV, but had no activity against heterologous HIV. 2) The efficacy of anti-gp41 mAb varied depending upon the epitope recognized and possibly the affinity of binding to gp41. 3) The polyclonal human anti-gp160 antibodies produced the immunotoxin with the broadest specificity for different HIV strains and the greatest specific activity. This is related to the polyclonal nature of the preparation rather than an increase in relative avidity of the antibody. 4) Activity of an immunotoxin is not a direct function of the binding of the antibody to the surface of infected cells. 5) The ability of an immunotoxin to halt the spread of infection through a tissue culture cell population is dependent upon the ability of the antibody to neutralize the virus as well as the activity of the toxin. Our data suggest that efficacious immunotoxins for the treatment of AIDS may be made with polyclonal anti-envelope antibodies derived from the serum of patients who have been infected with HIV or with appropriately chosen anti-gp41 antibodies.  相似文献
4.
Heteroaggregates containing anti-T3 cross-linked to anti-target cell antibodies have been shown to cause human T cells to lyse target cells that express antigens recognized by the anti-target cell antibody. In this study, we test targeted human T cells for the ability to lyse human tumor cells as a first step toward the application of this phenomenon to tumor immunotherapy. Several monoclonal anti-human tumor antibodies were assayed for binding to a number of human tumor lines and for the ability to promote specific tumor cell lysis when cross-linked with anti-T3. We found that anti-T3 cross-linked to anti-tumor monoclonal antibodies caused cloned human T cells and fresh peripheral blood T cells to lyse the tumor cells with the same specificity as predicted by the binding studies. Peripheral blood T cells were then tested in the presence of various heteroaggregates for the ability to lyse single cell suspensions prepared from fresh tumor or fresh normal tissue. These studies showed that heteroaggregates containing anti-T3 cross-linked to anti-tumor antibody cause fresh human T cells to specifically lyse fresh tumor cells, but not (with one exception) fresh normal cells.  相似文献
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A cell surface glycoprotein (designated T100) of apparent m.w. 100,000 by SDS-PAGE under reducing and nonreducing conditions was precipitated from NP-40 extracts of surface radiolabeled thymocytes from a variety of inbred strains of mice by the standard noncongenic Lyt-2.1-typing serum. The inbred stain distribution, trypsin sensitivity on intact cells, and apparent m.w. of T100 suggest that it is different from Lyt-2.1. Inheritance and expression of T100 suggest that it is determined by an allele at a single locus, and testing of CXB recombinant inbred strains and B6.C minor histocompatibility congenic strains suggest that this locus is linked to H-25. Antiserum absorption experiments, two-stage cytotoxicity assays, and results of immunoprecipitations performed after prebinding antibody to radiolabeled thymocytes suggest that some T100 is accessible to antibody on the intact cell surface. However, for unknown reasons the number of cells required to absorb anti-T100 precipitating activity from antiserum was much higher than for removal of anti-Lyt-2.1 activity. A molecule with properties of T100 was also detected on lymph node cells and on the AKTB-1 lymphoma.  相似文献
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Anti-Lyt-2.1 and anti-Lyt-3.1 sera were employed for sequential precipitation of NP-40 extracts of 125I-labeled C57BL/6-Lyt-2a, Lyt-3a thymocytes (Lyt-2.1, Lyt-3.1) to determine whether these alloantigenic determinants are present on the same or different molecular species. Treatment of extracts with anti-Lyt-3.1 serum and SaCI completely precipitated both Lyt-3.1 and Lyt-2.1-specific components, whereas treatment with anti-Lyt-2.1 serum reduced by approximately 37% the quantity of labeled species subsequently precipitable by anti-Lyt-3.1 serum. When 125I-labeled thymocytes were subjected to mild trypsinization before NP-40 extraction, the quantity of radioactive components precipitated by anti-Lyt-2.1 serum was essentially unchanged, but that of anti-Lyt-3.1-precipitable components was greatly reduced. Moreover, sequential precipitation of extracts of trypsinized thymocytes with anti-Lyt-2.1 and anti-Lyt-3.1 sera demonstrated that these molecular species were precipitated independently. Thus 1) Lyt-2.1 and Lyt-3.1 antigenic determinants appear to reside on different molecular species; 2) some Lyt-2.1- and Lyt-3.1-positive molecules appear to be complexed with each other in the NP-40 extract; and 3) this association of Lyt-2.1- and Lyt-3.1-positive species was dependent upon components that were labile to trypsinization of intact thymocytes.  相似文献
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