Human immunodeficiency virus type 1-neutralizing antibodies raised to a glycoprotein 41 peptide expressed on the surface of a plant virus.
An oligonucleotide encoding the amino acids 731-752 of the gp41 envelope protein of the human immunodeficiency virus type 1 strain IIIB, which is known to induce cross-reactive neutralizing antibodies in humans, was inserted into a full-length clone of the RNA encoding the coat proteins of cowpea mosaic virus (RNA 2 of CPMV). When transfected together with RNA 1 of CPMV, transcribed RNA 2 was able to replicate in plants and form infectious virions (CPMV-HIV). Purified virions were injected subcutaneously with alum adjuvant into adult C57/BL6 mice to determine their ability to stimulate ELISA and neutralizing antibody specific for HIV-1. Antisera to CPMV-HIV obtained after only two injections gave a strong ELISA response (mean of 1:25,800) using the free gp41 peptide as antigen, showing that the gp41 peptide incorporated into the chimera was immunogenic. The same antisera gave 97% neutralization of HIV-1 IIIB at 1:100 dilution, with a highly uniform response in all (six of six) animals tested. A third injection barely increased the neutralization titer. Normal mouse serum had no neutralizing activity. Antisera also strongly neutralized the HIV-1 strains RF and SF2. ELISA and neutralizing activity to HIV-1 IIIB declined after the second injection and were undetectable after 7 weeks, but were restimulated to the same level after the third injection. Neutralization was marginally more stable after the third injection. Antibody specific for CPMV epitopes was equally short lived. A bonus of this system was unexpected neutralizing activity specifically stimulated by unmodified CPMV virions, although this amounted to no more than 10% of the neutralizing activity stimulated by the CPMV-HIV chimera.(ABSTRACT TRUNCATED AT 250 WORDS)
McLain
L
L
Department of Biological Sciences, University of Warwick, Coventry, UK.
Porta
C
C
Lomonossoff
G P
GP
Durrani
Z
Z
Dimmock
N J
NJ
D000818:Animals; D000918:Antibody Specificity; D002213:Capsid / Q000096:biosynthesis; D002460:Cell Line; D003001:Cloning, Molecular; D017798:Comovirus / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D015483:HIV Antibodies / Q000276:immunology*; D015488:HIV Antigens / Q000096:biosynthesis / Q000276:immunology*; D015700:HIV Envelope Protein gp41 / Q000096:biosynthesis / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology; D011995:Recombination, Genetic; D014771:Virion / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure
D015483:HIV Antibodies; D015488:HIV Antigens; D015700:HIV Envelope Protein gp41; D011994:Recombinant Proteins