ISSN:0889-2229    

DOI:10.1089/aid.1989.5.1

年代:1989

数据来源: MAL

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.5

年代:1989

数据来源: MAL

摘要:

Three-dimensional computer models for two segments of the C terminus of gp41, the transmembrane AIDS envelope protein, which may form amphipathic α-helices, have been generated using structure prediction techniques combined with energy minimization and molecular dynamics simulations. Regions gp41(772–790) and gp41(828–848) of the HXB2 strain of HIV-1 display extraordinarily high hydrophobic moment maxima as α-helices and when in an antiparallel conformation exhibit charge complementarity, implying that they may bind with each other and associate with the membrane. The feasibility of this hypothesis was tested in a series of computer simulations of these peptides, extended by several residues to include additional charge pairing. Beginning with a trial structure in the form of antiparallel α-helices of segments 770–794 and 824–856, systematic axial rotations and displacements were used to generate alternative initial states. Molecular dynamics simulations with α-helical torsional restraints yielded several approximately cylindrical dimeric structures highly stabilized by numerous salt links and other hydrogen bonds. This suggests that these two regions may fold back on each other in antiparallel fashion to form a loop in the tertiary structure over residues 770–856, with the loop closed by membrane-associated amphipathic α-helices with charged sides facing each other. We speculate that such structures could aggregate to form channels or otherwise destabilize the membrane, thereby contributing to the cytopathic effects of the gp12

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.7

年代:1989

数据来源: MAL

摘要:

The immune responses produced by four macaques inoculated intradermally with a recombinant vaccinia virus that expresses the envelope gene of human immunodeficiency virus (HIV) were analyzed. Antibody capable of immunoprecipitating the glycosylated envelope protein precursor gp160 was detected in all animals within 3 weeks after the primary intradermal vaccination. The level of antibody was increased following a booster inoculation, and the sera from three of the four animals were then capable of immunoprecipitating gp120. Sera from two of the macaques with anti-gp120 antibody were able to prevent syncytium formation mediated by the parent HIV but not that induced by an unrelated HIV isolate. The fusion-inhibiting antibody was directed toward the highly variable central portion of the gp120 molecule since the effect was abrogated by incubation with PB1. The latter is a recombinant protein produced inEscherchia colicontaining amino acids 295–474, a major neutralizing epitope. Sera from the three macaques with anti-gp120 neutralized HIV infectivity in an isolate-specific manner. The serum with highest neutralizing activity was also best at inhibiting syncytium formation. In contrast to the isolate-specific nature of the neutralizing antibody, T lymphocytes from immunized animals proliferated in response to divergent HIV isolates as well as to purified gp120. These studies provide baseline immunologic information for further development of recombinant vaccinia virus vector

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.23

年代:1989

数据来源: MAL

摘要:

A total of six amino acid sequences encoded in conserved regions of the HIV-env(three from gp120 and three from gp41) were selected as potential antigenic domains. These sequences (11-20 amino acids) were fused to the NH2terminus of β-galactosidase by recombinant DNA techniques, and the purified chimeric proteins were used to titer (by immunodots) 75 sera from HIV-infected individuals of various stages. All the HIV antigens were recognized by some or all the HIV-seropositive sera but by none of the control sera. Of the three conserved domains in gp41, two are highly immunodominant. All (100%) HIV-seropositive sera reacted with one of these immunodominant domains in titers (approximately 1:100,000) almost two orders of magnitude higher than any other tested domain. This emphasizes the diagnostic value of the epitopes (ERYLKDQLLGIWGCSGKLIC) previously (see Refs. 11 and 12) identified in this domain. A decrease in average antibody titers is observed in late stages of infection for all the antigens tested, yet distribution of antibody reactivity was independent of stage for only three of the six domains. A significantly higher proportion of reactivity of seropositive sera in early stage (62%) compared with late stage (11%) of infection was found for a domain (NVTENFNMWKN) mapped at the NH2 terminus of gp120; serum antibody reactivity with this domain also correlated with a lack of culturable HIV in blood mononuclear cells

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.33

年代:1989

数据来源: MAL

摘要:

The only animal that can be reproducibly infected with HIV, and that thus provides an experimental system for testing the effectiveness of prototype vaccines, is the chimpanzee. We compared proliferative responses to HIV and to vaccinia virus (VV) antigens of lymphocytes taken at various times from chimpanzees vaccinated with recombinant VV expressing different HIV genes. Animals were immunized with the original VV strain, as control, or with constructs expressing gp160 (VV160) given exclusively or in combination with one or two other constructs producing p25 (VV25),F/3′-orf(VVF), or the human interleukin-2 (IL-2) gene, which was included in an attempt to amplify immune responses. Irrespective of the HIV gene utilized, lymphocyte proliferation to HIV was usually weak and rapidly decreased after each inoculation, contrasting with strong and sustained responses to VV. Lack of adequate recall reactivity after challenge with fixed autologous lymphocytes expressing VV-produced HIV antigens indicated that vaccination resulted only in low levels of HIV-specific memory cell priming. The use of IL-2-producing VV did not lead to increased responsiveness. Reactivity to soluble purified gp160, but not to p25, could be detected in PBL from animals that had received both VV160 and VV25, while immunization with VVF resulted in a significant response to this protein in one of two animals. The transient nature of T cell reactivity to HIV might explain why, in similar studies, chimpanzees were not protected from infection with live HI

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.41

年代:1989

数据来源: MAL

摘要:

We have raised a rabbit monospecific antibody against a synthetic peptide derived from a sequence within the COOH-terminal portion of the reverse transcriptase (RT) of HIV-1. This sequence was also found to be conserved in the predicted amino acid sequence of HIV-2. The antibody, designated C2003, cross-reacted with HIV-2 RT on immunoblots of HIV-2 virus extract and directly inhibited HIV-2 RT activity. Fractionation of HIV-2 RT by immunoaffinity chromatography with C2003 antibody yielded a pair of viral proteins of 68 and 55 kD associated with both RT and RNAse H activities. Both proteins were found to be highly immunogenic, recognized by 11 of 11 human sera that previously tested positive for antibodies to HIV-2 antigens in immunoblot assays.

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.51

年代:1989

数据来源: MAL

摘要:

Eight fragments derived from the HIV-1polgene were expressed as recombinant polypeptides inEscherichia coli. The fragments were from the portion of thepolgene that encodes the reverse transcriptase. The expressed peptides were analyzed immunologically with sera from HIV-1-infected individuals. Three distinct immunogenic epitopes were identified. These determinants are presumably located on the surface of the native reverse transcriptase. Each epitope was included in a fusion protein that was expressed at high levels in bacteria. These proteins may provide reagents of potential diagnostic value.

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.61

年代:1989

数据来源: MAL

摘要:

An EBV-transformed lymphoblastoid B cell clone (A12) derived from peripheral blood lymphocytes of an HIV-1-infected individual is described. The immunoglobulin isotype produced by this clone was IgM, and Southern blot analysis of immunoglobulin gene rearrangement showed a monoclonal pattern. The A12 monoclonal antibody was specific for the p24 product of the HIV-1gaggene. This clone is now in continuous culture for more than 8 months and no changes in its biologic properties have been observed.

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.73

年代:1989

数据来源: MAL

摘要:

The long terminal repeats (LTRs) of the human immunodeficiency virus (HIV) the Rous sarcoma virus (RSV) and thecopia Drosophilaretrotranposon were compared in their capacity to direct expression of the bacterialcat(chloramphenicol acetyltransferase) gene in human, murine, andDrosophilacell lines. The results indicate that HIV and RSV LTR expression is post transcriptionally repressed in theDrosophilacells whilecopiaLTR expression is post-transcriptionally repressed in the human and murine cells.

ISSN:0889-2229    

DOI:10.1089/aid.1989.5.79

年代:1989

数据来源: MAL