The presence of antibodies against HIV peptides in the sera of alloimmune mice and thalassemic patients is due to a polyclonal activation mechanism.
This paper analyses the HIV-1 gp120 epitope specificity and activation mechanisms (i.e., polyclonal versus oligoclonal) of antibodies present in the sera of alloimmune mice and humans. Sera from CBA mice engrafted with C57BL/6 lymphoid cells significantly reacted against the gp120-derived peptide as 261-270, which shares high homology with the membrane-proximal domain of HLA class II beta-chains (HLA/ gp120) and against the HIV gp120 V3 loop-derived peptides DP32 (HIV-1 MN-derived as 302-334) and C53 (HIV-1 IIIB-derived as 304-318). The same sera also reacted against the HIV-unrelated peptide necdin. Moreover, sera from BALB/c mice injected with LPS presented antibodies reacting against both HIV-related and -unrelated peptides, suggesting that similar mechanisms are shared in alloimmune and LPS-treated mice. A similar analysis was then performed on the sera of patients affected with beta-thalassemia major, receiving at least 10 blood transfusions/year. In particular, 15 of 58 (26%) sera from HIV-uninfected thalassemic patients showed a significantly reactivity against the HLA/gp 120-derived peptides. Moreover, 22 of 58 (38%) sera from the same cohort showed a significant reactivity against DP32 peptide. This reactivity was related to a polyclonal activation mechanism since the DP32-reactive sera significantly bound a panel of HIV-unrelated peptides, as observed by testing 22 sera against necdin, 21 against HSP65 kDa, 21 against amyloid-1, and 17 against MAGE-1 peptides. Moreover, a significant increase of IgG concentration was also observed in all thalassemic sera, when compared to healthy controls, without regard to the anti-gp120 antibody reactivity. Taken together, these results indicate that (i) allogeneic stimuli may induce anti-gp120 antibodies in CBA and in 38% of polytransfused patients and (ii) this reactivity is related to a polyclonal activation mechanism but not to a heightened concentration of IgG.
Fraziano
M
M
Department of Biology, University of Rome Tor Vergata, Italy.
Montesano
C
C
Lombardi
V R
VR
Marchione
O P
OP
Colizzi
V
V
D000682:Amyloid / Q000276:immunology; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins; D018834:Chaperonin 60; D018833:Chaperonins / Q000276:immunology; D015483:HIV Antibodies / Q000097:blood; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007518:Isoantibodies / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D017086:beta-Thalassemia / Q000097:blood* / Q000276:immunology / Q000821:virology
D000682:Amyloid; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018834:Chaperonin 60; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D007074:Immunoglobulin G; D007518:Isoantibodies; C074119:heat-shock protein 65, Mycobacterium; D018833:Chaperonins