6th International AIDS Conference


San Francisco, California, USA — June 20-23, 1990

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Recombinant bacteria expressing at the surface gp120 epitopes of HIV 1 as live immunogens.

Int Conf AIDS 1990 Jun 20-23; 6:324 (abstract no. 1042)
Maffei L, Tattanelli M, Paini C, Hofnung M, Siccardi AG, Andronico F; Dipartimento di Biologia e Genetica, Universita di Milano, Italy

OBJECTIVE: We have used the LamB "exposition" vector system to express, on the surface of recombinant bacteria, two HIV 1 gp120 epitopes chosen among the most probable predicted antigenic sites. We verified that the recombinant epitopes were accessible to antibodies on the surface of live bacteria and we tested them as antigens and as immunogens to obtain antisera reactive with the native viral gp120.

METHODS: Oligonucleotides 6865-6892 (OAB 155) and 7273-7311 (OAB 158) of the HIV 1 sequence were cloned into the Bam H1 site of the LamB gene carried by pAJC264. Total bacterial lysates of recombinant clones were tested by SDS-PAGE and Western-Blot with a serum against the LamB protein (a maltoporine located in the outer membrane of E.coli K12) and one of the recombinant proteins was directly extracted from the bacterial membrane and tested by the same methods. Balb/c mice were immunized with live recombinant bacteria. Preimmune and immune sera were assayed by ELISA and Western-Blot on the corresponding viral proteins.

RESULTS: We obtained stable recombinant LamB proteins containing two HIV 1 epitopes accessible to antibodies on the surface of live bacteria. To test the ability of the two HIV 1 epitopes to be efficiently presented to the immune system, we immunized Balb/c mice with live bacteria. The immune sera proved to be reactive with HIV 1 lysates and with recombinant gp120 in ELISA assays. The same sera efficiently decorated recombinant gp160 and gp120 in Western-Blot assays.

CONCLUSION: LamB recombinant proteins bearing HIV 1 epitopes are indeed exported to the surface of recombinant bacteria and are able to elicit an immune response against native gp120. The use of the LamB "exposition" vector system might thus lead to the development of new strategies for live vaccines also against AIDS.

Keywords: AEGIS, HIV-1, Epitopes, Blotting, Western, Recombinant Proteins, Immune Sera, Enzyme-Linked Immunosorbent Assay, Escherichia coli, Animal, Mice, microbiology, ICA6KWDaegis,hiv-1,epitopes,blotting,western,recombinantproteins,immunesera,enzyme-linkedimmunosorbentassay,escherichiacoli,animal,mice,microbiology,ica6

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