Serum IgA-mediated neutralization of HIV type 1.
The sera of 33 HIV-1-infected individuals, previously shown to neutralize HIV-1MN in vitro, were screened by ELISA for IgA reactivity against rgp120MN and a synthetic V3MN loop peptide. Six were selected for evaluation of the effect of serum IgA from infected individuals on the in vitro infection of susceptible target cells by HIV-1MN. By using protein G immobilized on Sepharose, we depleted the sera of IgG to a level undetectable by nephelometry and viral envelope-specific ELISA. The IgA component of the IgG-depleted serum was affinity purified with immobilized jacalin, a lectin that selectively binds the IgA1 fraction of human Ig. IgG-depleted sera and purified IgA1 serum fractions showing IgA reactivity against rgp120MN and V3MN by ELISA inhibited the in vitro infection of CEM-ss cells by HIV-1MN, but sera depleted of both IgG and IgA1 did not. These data show that, like serum IgG, serum IgA from selected HIV-1-infected individuals is capable of neutralizing HIV-1MN in vitro. The biologic significance of this observation and the identities of serum IgA-recognized HIV-1 neutralization epitopes remain to be determined.
Burnett
P R
PR
U.S. Army Dental Research Detachment, Washington, DC 20307.
VanCott
T C
TC
Polonis
V R
VR
Redfield
R R
RR
Birx
D L
DL
D015483:HIV Antibodies / Q000097:blood*; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015658:HIV Infections / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D066298:In Vitro Techniques; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000276:immunology
D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D007070:Immunoglobulin A; D010446:Peptide Fragments