Cross -Reactivity of the V3-Specific Antibodies with the Human C1q

2001 ◽  
Vol 56 (11-12) ◽  
pp. 1135-1143 ◽  
Author(s):  
Marijana Petković ◽  
Radmila Metlaš

Abstract It has been previously shown that the sequence similarity between a portion of the enve­lope glycoprotein 120 (gp120) from the human immunodeficiency virus type-1 (HIV-1) and several types of human collagen and collagen-like molecules exists. That observation led to the suggestion that the antibodies against the third hypervariable region (V3) of HIV-1 gpl20 (V3-specific antibodies) might have a role in the autoimmune phenomena observed in HIV-infected persons. In this study we have examined the cross-reactivity of the V3-specific anti­ bodies purified from sera of HIV-infected individuals, sera obtained from the rheumatoid arthritis and systemic lupus erythematosus patients, as well as from the sera of healthy volun­ teers with the separate chains of a subcomponent of the first component of the human com­ plement system, C1q. Our results show that the V3-specific antibodies are present in the sera of the HIV-infected individuals, patients suffering of the systemic autoimmune diseases as well as in the sera of healthy volunteers. Whereas these antibodies appeared in the HIV+-sera after antigen challenge, those present in the H IV --sera probably represent the antibod­ ies that are cross-reactive with the antigen. V3-reactive antibodies can be purified by affinity chromatography and they were highly specific for the V3-peptide. Additionally, they showed cross-reactivity with the separate chains of the human C1q as well as with the chicken colla­ gen type VI. Possible physiological implications are discussed.

2003 ◽  
Vol 84 (10) ◽  
pp. 2715-2722 ◽  
Author(s):  
Gkikas Magiorkinis ◽  
Dimitrios Paraskevis ◽  
Anne-Mieke Vandamme ◽  
Emmanouil Magiorkinis ◽  
Vana Sypsa ◽  
...  

Recombination plays a pivotal role in the evolutionary process of many different virus species, including retroviruses. Analysis of all human immunodeficiency virus type 1 (HIV-1) intersubtype recombinants revealed that they are more complex than described initially. Recombination frequency is higher within certain genomic regions, such as partial reverse transcriptase (RT), vif/vpr, the first exons of tat/rev, vpu and gp41. A direct correlation was observed between recombination frequency and sequence similarity across the HIV-1 genome, indicating that sufficient sequence similarity is required upstream of the recombination breakpoint. This finding suggests that recombination in vivo may occur preferentially during reverse transcription through the strand displacement-assimilation model rather than the copy-choice model.


1990 ◽  
Vol 172 (4) ◽  
pp. 1151-1158 ◽  
Author(s):  
B Ardman ◽  
M A Sikorski ◽  
M Settles ◽  
D E Staunton

Sera from human immunodeficiency virus type 1 (HIV-1)-infected and -noninfected individuals were screened for antibodies that could bind to native T cell differentiation antigens. Antibodies that could immunoprecipitate CD43 (sialophorin, leukosialin) from a T cell lymphoma line were detected in sera from 27% of patients, and antibodies that could bind specifically to transfected cells expressing CD43 were detected in 47% of patients. The anti-CD43 antibodies were related to HIV-1 infection in that no patients with other chronic viral infections or systemic lupus erythematosus contained such antibodies in their sera. The anti-CD43 autoantibodies bound to a partially sialylated form of CD43 expressed by normal human thymocytes, but not by normal, circulating T lymphocytes. However, the determinant(s) recognized by the anti-CD43 autoantibodies was present on a large proportion of circulating T lymphocytes, but masked from antibody recognition by sialic acid residues. These results demonstrate that HIV-1 infection is specifically associated with the production of autoantibodies that bind to a native T cell surface antigen.


2001 ◽  
Vol 75 (12) ◽  
pp. 5526-5540 ◽  
Author(s):  
S. W. Barnett ◽  
S. Lu ◽  
I. Srivastava ◽  
S. Cherpelis ◽  
A. Gettie ◽  
...  

ABSTRACT Partial deletion of the second hypervariable region from the envelope of the primary-like SF162 virus increases the exposure of certain neutralization epitopes and renders the virus, SF162ΔV2, highly susceptible to neutralization by clade B and non-clade B human immunodeficiency virus (HIV-positive) sera (L. Stamatatos and C. Cheng-Mayer, J. Virol. 78:7840–7845, 1998). This observation led us to propose that the modified, SF162ΔV2-derived envelope may elicit higher titers of cross-reactive neutralizing antibodies than the unmodified SF162-derived envelope. To test this hypothesis, we immunized rabbits and rhesus macaques with the gp140 form of these two envelopes. In rabbits, both immunogens elicited similar titers of binding antibodies but the modified immunogen was more effective in eliciting neutralizing antibodies, not only against the SF162ΔV2 and SF162 viruses but also against several heterologous primary HIV type 1 (HIV-1) isolates. In rhesus macaques both immunogens elicited potent binding antibodies, but again the modified immunogen was more effective in eliciting the generation of neutralizing antibodies against the SF162ΔV2 and SF162 viruses. Antibodies capable of neutralizing several, but not all, heterologous primary HIV-1 isolates tested were elicited only in macaques immunized with the modified immunogen. The efficiency of neutralization of these heterologous isolates was lower than that recorded against the SF162 isolate. Our results strongly suggest that although soluble oligomeric envelope subunit vaccines may elicit neutralizing antibody responses against heterologous primary HIV-1 isolates, these responses will not be broad and potent unless specific modifications are introduced to increase the exposure of conserved neutralization epitopes.


2001 ◽  
Vol 82 (5) ◽  
pp. 1095-1106 ◽  
Author(s):  
E. Baldrich-Rubio ◽  
S. Anagonou ◽  
K. Stirrups ◽  
E. Lafia ◽  
D. Candotti ◽  
...  

A human immunodeficiency virus type 1 (HIV-1B76) originating from Benin (West Africa) was isolated and characterized. The patient had severe clinical AIDS and presented an unusual serological profile. Only one out of five different detection assays was able to demonstrate the presence of antibodies to HIV, whereas confirmatory assays remained indeterminate. In contrast, both plasma viral load and p24 antigen level were unusually high. HIV-1 infection was proved by viral RNA and proviral DNA amplification. HIV-1B76 partially purified lysate reacted strongly with all anti-HIV-1-positive sera from the region but B76 plasma did not react with subtype A control viral antigen. This patient is likely to have had severe acquired immune dysfunction explaining her lack of immunological reactivity. Phylogenetic analysis of the genome identified a complex HIV-1 A/G/J recombinant. The gag and pol genes, and the majority of nef,are characteristic of subtype A; the gag/pol junction, the 3′ end of pol, vpu and env genes were characteristic of subtype G; vif, vpr and the 5′ end of nef were subtype J. In addition, part of the HIV-1B76 genome had considerable sequence similarity with the previously described CRF06 cpx (BFP90) isolate. HIV-1B76 did not exhibit any remarkable replication properties or cell tropism in vitro.


2002 ◽  
Vol 76 (2) ◽  
pp. 644-655 ◽  
Author(s):  
Peng Fei Zhang ◽  
Peter Bouma ◽  
Eun Ju Park ◽  
Joseph B. Margolick ◽  
James E. Robinson ◽  
...  

ABSTRACT The human serum human immunodeficiency virus type 1 (HIV-1)-neutralizing serum 2 (HNS2) neutralizes many primary isolates of different clades of HIV-1, and virus expressing envelope from the same donor, clone R2, is neutralized cross-reactively by HIV-immune human sera. The basis for this cross-reactivity was investigated. It was found that a rare mutation in the proximal limb of variable region 3 (V3), 313-4 PM, caused virus pseudotyped with the R2 envelope to be highly sensitive to neutralization by monoclonal antibodies (MAbs) directed against conformation-sensitive epitopes at the tip of the V3 loop, such as 19b, and moderately sensitive to MAbs against CD4 binding site (CD4bs) and CD4-induced (CD4i) epitopes, soluble CD4 (sCD4), and HNS2. In addition, introduction of this sequence by mutagenesis caused enhanced sensitivity to neutralization by 19b, anti-CD4i MAb, and HNS2 in three other primary HIV-1 envelopes and by anti-CD4bs MAb and sCD4 in one of the three. The 313-4 PM sequence also conferred increased infectivity for CD4+ CCR5+ cells and the ability to infect CCR5+ cells upon all of these four and two of these four HIV-1 envelopes, respectively. Neutralization of R2 by HNS2 was substantially inhibited by the cyclized R2 V3 35-mer synthetic peptide. Similarly, the peptide also had some lesser efficacy in blocking neutralization of R2 by other sera or of neutralization of other primary viruses by HNS2. Together, these results indicate that the unusual V3 mutation in the R2 clone accounts for its uncommon neutralization sensitivity phenotype and its capacity to mediate CD4-independent infection, both of which could relate to immunogenicity and the neutralizing activity of HNS2. This is also the first primary HIV-1 isolate envelope glycoprotein found to be competent for CD4-independent infection.


2001 ◽  
Vol 75 (18) ◽  
pp. 8752-8760 ◽  
Author(s):  
James R. Taylor ◽  
Katherine C. Kimbrell ◽  
Robert Scoggins ◽  
Marie Delaney ◽  
Lijun Wu ◽  
...  

ABSTRACT The presence or absence of the receptor CD4 and the coreceptors CCR5 and CXCR4 restrict the cell tropism of human immunodeficiency virus type 1 (HIV-1). Despite the importance of thymic infection by HIV-1, conflicting reports regarding the expression of HIV-1 coreceptors on human thymocytes have not been resolved. We assayed the expression and function of the major HIV-1 coreceptors, CCR5 and CXCR4, as well as CCR4 and CCR7 as controls, on human thymocytes. We detected CCR5 on 2.5% of thymocytes, CXCR4 on 53% of the cells, and CCR4 on 16% and CCR7 on 11% of human thymocytes. Moreover, infection by R5 HIV-1 did not significantly induce expression of CCR5. We found that two widely used anti-CCR5 monoclonal antibodies cross-reacted with CCR8, which may account for discrepancies among published reports of CCR5 expression on primary cells. This cross-reactivity could be eliminated by deletion of amino acids 2 through 4 of CCR8. Chemotaxis assays showed that SDF-1, which binds CXCR4; MDC, which binds CCR4; and ELC, which binds CCR7, mediated significant chemotaxis of thymocytes. In contrast, MIP-1β, whose receptor is CCR5, did not induce significant chemotaxis. Our results indicate that CXCR4, CCR4, CCR7, and their chemokine ligands may be involved in thymocyte migration during development in the thymus. CCR5 and its ligands, however, are likely not involved in these processes. Furthermore, the pattern of CCR5 and CXCR4 expression that we found may explain the greater susceptibility of human thymocytes to infection by HIV-1 isolates capable of using CXCR4 in cell entry compared to those that use only CCR5.


2006 ◽  
Vol 80 (12) ◽  
pp. 6093-6105 ◽  
Author(s):  
Robyn L. Stanfield ◽  
Miroslaw K. Gorny ◽  
Susan Zolla-Pazner ◽  
Ian A. Wilson

ABSTRACT Human monoclonal antibody 2219 is a neutralizing antibody isolated from a human immunodeficiency virus type 1-infected individual. 2219 was originally selected for binding to a V3 fusion protein and can neutralize primary isolates from subtypes B, A, and F. Thus, 2219 represents a cross-reactive, human anti-V3 antibody. Fab 2219 binds to one face of the variable V3 β-hairpin, primarily contacting conserved residues on the N-terminal β-strand of V3, leaving the V3 crown or tip largely accessible. Three V3/2219 complexes reveal the antibody-bound conformations for both the N- and C-terminal regions that flank the V3 crown and illustrate how twisting of the V3 loop alters the relative dispositions and pairing of the amino acids in the adjacent V3 β-strands and how the antibody can accommodate V3 loops with different sequences.


2005 ◽  
Vol 79 (8) ◽  
pp. 4828-4837 ◽  
Author(s):  
Brandon L. Walter ◽  
Kathy Wehrly ◽  
Ronald Swanstrom ◽  
Emily Platt ◽  
David Kabat ◽  
...  

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) isolates vary in their ability to infect macrophages. Previous experiments have mapped viral determinants of macrophage infectivity to the V3 hypervariable region of the HIV-1 envelope glycoprotein. In our earlier studies, V1 and V2 sequences of HIV-1 were also shown to alter the ability of virus to spread in macrophage cultures, whereas no effect was seen in lymphocyte cultures. In the present study, determinants that allowed certain HIV-1 clones to infect and spread in macrophages were primarily mapped to the V2 region and were found to act by influencing early events of viral infection. By an assay of viral entry into macrophages, it was shown that viruses with the V2 region from the Ba-L strain of HIV-1 had >10-fold-higher entry efficiency than viruses with the V2 region derived from the NL4-3 strain. V1 region differences between these groups caused a twofold difference in entry. The known low expression of CD4 on macrophages appeared to be important in this process. In entry assays conducted with HeLa cell lines expressing various levels of CD4 and CCR5, low levels of CD4 influenced the efficiency of entry and fusion which were dependent on viral V1 and V2 envelope sequences. In contrast, no effect of V1 or V2 was seen in HeLa cells expressing high levels of CD4. Thus, the limited expression of CD4 on macrophages or other cell types could serve as a selective factor for V1 and V2 envelope sequences, and this selection could in turn influence many aspects of AIDS pathogenesis in vivo.


1998 ◽  
Vol 36 (1) ◽  
pp. 123-127 ◽  
Author(s):  
John N. Nkengasong ◽  
Chantal Maurice ◽  
Stéphania Koblavi ◽  
Mireille Kalou ◽  
Celestin Bile ◽  
...  

Serologic distinction between human immunodeficiency virus type 1 (HIV-1) and HIV-2 infection is made difficult because of the cross-reactivity and high cost of existing differentiation assays. An evaluation of a strategy based on a combination of monospecific enzyme-linked immunosorbent assays (ELISAs) (CME), was carried out in Abidjan, Ivory Coast, where both HIV-1 and HIV-2 are present, to determine its accuracy and cost-effectiveness. A total of 1,608 (428 HIV-1-positive, 361 HIV-2-positive, 371 dually HIV-1 and HIV-2 [HIV-D] reactive, and 448 HIV-negative) sera that had been serotyped by a line immunoassay (Peptilav) were tested retrospectively by an HIV-1-monospecific (Wellcozyme HIV Recombinant ELISA) and an HIV-2-monospecific (ICE*-HIV-2) assay. The CME strategy gave concordant results for all of the 428 sera scored as HIV-1 by Peptilav. Of the 361 sera scored as HIV-2 by Peptilav, 316 (87.5%) were scored as HIV-2 by CME; the remaining 45 sera were positive by both monospecific ELISAs (mean optical density ratios, 1.36 for Wellcozyme and 11.30 for ICE*-HIV-2) and were classified as HIV-D by CME. Of the 371 sera classified as HIV-D by Peptilav, 344 (92.7%), 21, and 6 were scored as HIV-D, HIV-1, and HIV-2, respectively, by CME. Additional testing of the discrepant samples by two HIV differentiation assays (RIBA and INNO-LIA) gave results that agreed with those by CME for most of the sera. In addition, 267 other sera were tested prospectively by both CME and Peptilav. In the prospective evaluation, CME results agreed with those by Peptilav for all 106 HIV-1 sera and 40 of the 41 HIV-2 sera. However, of the 120 sera scored as HIV-D by Peptilav, 69 (57.5%), 47 (39.2%), and 4 (3.3%) were scored as HIV-D, HIV-1 only, and HIV-2 only, respectively, by CME. All 47 samples scored as HIV-1 by CME and two of four HIV-2 sera gave concordant results by RIBA, whereas 29 of 47 sera scored as HIV-1 by CME and all four HIV-2 sera gave concordant results by INNO-LIA. The reagent cost for the CME strategy was 59% lower than the cost of the Peptilav strategy. These results suggest that a combination of highly sensitive and specific commercially available monospecific ELISAs is a reliable and cost-effective strategy for type-specific serodiagnosis of HIV-1 and HIV-2 infections in HIV-seropositive persons and therefore represents a recommended strategy in areas where both HIV-1 and HIV-2 are endemic.


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