Recognition of defined epitopes by affinity-purified anti-immunoglobulin fab autoantibodies isolated from HIV-infected humans.

Infection of humans with HIV-1 has previously been independently shown to result in the generation of autoantibodies (AAbs) reactive with immunoglobulin Fab fragments (Heidelberg), and with autoantibodies to T-cell receptors (TCRs) (Tucson). Here, we carry out epitope mapping studies of affinity-purified AAbs to Fab fragments prepared from individual HIV-positive patients for their capacity to bind recombinant constructs and peptide-defined epitopes modeling TCR and Ig light chains. Some affinity-purified autoantibodies reacted strongly with TCRs expressed by intact T-cells, and recombinant Valpha/Vbeta constructs as well as with certain synthetic peptide epitopes.

Physical and epitope analysis of a recombinant human T-cell receptor V alpha/V beta construct support the similarity to immunoglobulin.

The genetic organization and protein structure of T-cell receptors (TCR) and immunoglobulins (Ig) are remarkably similar. Through recombinant, physical, and peptide-based immunological studies we demonstrated that rabbit antisera generated against a recombinant single-chain TCR (scTCR) react with defined peptide epitopes of their constituent TCR alpha and beta chains. These antisera cross-react with the lambda light-chain Mcg as well as with peptides duplicating its covalent structure.

Characterization of monoclonal antibodies to Pseudomonas aeruginosa type A flagellar antigen.

Flagellar murine MAbs (53B and 29) to strain a-type 170018 (a0,a3,a4, 45 kDa) and a human a-type MAb were studied in ELISA, Immunoblot, colony blot, agglutination and motility assays to evaluate the degree of cross-reactivity within the dominant a0 epitope. No specific effect of possible subtypes (a1, a2, a3, a4) was observed. An association of cross-reactivity and molecular weight was observed for 53B.

Analysis of autoantibodies to T-cell receptors among HIV-infected individuals: epitope analysis and time course.

Individuals seropositive for human immunodeficiency virus type 1 (HIV) express elevated levels of autoantibodies (AAbs) directed against recombinant T-cell receptors (TCRs) and synthetic peptide epitopes duplicating beta chain markers. We performed longitudinal studies of anti-TCR AAbs in HIV-1-infected individuals, making comparisons with uninfected sera and sera from other individuals infected with a nonviral agent. We determined levels of autoantibodies by titration using enzyme-linked immunosorbent assay (ELISA) and developed a means for characterizing "autoantibody CDR recognition spectrotypes" for individual sera.