Important note: Information in this article was accurate in 1994. The state of the art may have changed since the publication date.
Subtotal immunity and virus suppression induced by recombinant SIV vaccines.
Symp Nonhum Primate Models AIDS. 1993 Sep 19-22;11:abstract no. 15. Unique Identifier : AIDSLINE PRIM11/94191607 Hoover EA; Israel ZR; Edmonson PF; Mossman SP; O'Neil SP; Bex F; Thiriart C; Fabry L; Van Opstal O; Bruck C; et al; Colorado State University, Fort Collins 80523.
Abstract:
We evaluated the efficacy of SIV recombinant envelope (env) and gag proteins and whole inactivated virus (wiv) vaccines, with or without recombinant live vaccinia vector (vv) priming, in protecting 23 rhesus macaques from SIVmac251 clone BK28 challenge. We used serial and terminal assessment of virus replication, provirus burden, and antiviral immune responses to define 5 post-challenge categories of immunity reflecting degrees of resistance to SIV infection as follows: (1) No infection/sterilizing immunity, was defined by absence of both detectable viral replication and provirus and was found only in wiv-immunized animals. (2) Abortive infection/strong immunity was designated when infectious virus or proviral DNA were detected once but never thereafter, a response found in 2 of 12 recombinant env-immunized animals. (3) Significant suppression of infection/subtotal immunity was defined by transient early virus recovery and subsequent very low residual provirus burden. This response occurred in vv-wiv- or env-vaccinated macaques. (4) Partial suppression of infection/partial immunity was identified when infectious virus was no longer isolatable from blood yet provirus or virus was detectable from the lymphoid tissue compartment terminally. This response was found in the majority (7 of 12) of env or env+gag-immunized animals. (5) Active infection/no immunity was indicated by persistent positive virus isolation, high proviral load, and rising SIV antibody titers and occurred in all 5 controls and 2 vv-gag-env-immunized animals. Quantitative PCR performed on terminal tissues from all groups revealed provirus burden to be highest in lymph nodes, intermediate in spleen, and least in the circulating blood mononuclear cells. In addition, the effectiveness of each vaccine was directly reflected by the total provirus burden post challenge. These results demonstrate that significant yet subtotal immunity is induced by SIV recombinant protein vaccines and reiterate the protective effect of inactivated wiv vaccines produced in human cells. The results of this study are pertinent to field studies with recombinant HIV vaccines in which it is quite conceivable that incomplete yet significant protection may be achieved, thus recognition and classification of intermediate states of immunity and virus suppression will become important in vaccine evaluation.
Keywords: Animal Antibodies, Viral/*BLOOD DNA, Viral/ANALYSIS Gene Products, env/IMMUNOLOGY Gene Products, gag/IMMUNOLOGY Macaca Polymerase Chain Reaction Proviruses/ISOLATION & PURIF Simian Acquired Immunodeficiency Syndrome/*IMMUNOLOGY/PREVENTION & CONTROL SIV/*IMMUNOLOGY/ISOLATION & PURIF Vaccines, Synthetic/*THERAPEUTIC USE Viral Vaccines/*THERAPEUTIC USE Virus Replication ABSTRACT 940730
M9470911
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Important note: Information in this article was accurate in 1994. The state of the art may have changed since the publication date.
