Anti-Tcrb Monoclonal antibody, clone I68-608

In HIV-I-infected individuals, the CD8(+) CD28(-) T cell subset is considerably expanded and is frequently the largest subset of T cells found in peripheral blood. It has been assumed, but not proven, that CD8(+) CD28(-) T cells derive from CD8(+) CD28(+) T cells in vivo. To further study the ontogeny of CD8(+) CD28(-) T cells, we have performed analyses of the complementarity determining region 3 (CDR3) of the TCRB of CD8(+) CD28(+) and CD8(+) CD28(-) T cells from the peripheral blood of HIV-l-infected individuals. When cells from the same individual were compared, expanded peaks in CDR3 length analysis within a given BV family were frequently observed at the same location in both CD8(+) subsets (p < 0.001). Sequencing of cDNA corresponding to dominant peaks revealed the presence of identical expanded CD8(+) T cell clones within both the CD28(+) and CD28(-) subsets on eight of nine attempts. Our results show that CD8(+) CD28(+) and CD8(+) CD28(-) T cells are phenotypic variants of the same lineage, most likely evolving from CD8(+) CD28(+) to end-stage CD8(+) CD28(-) T cells.

Human cDNA probe H1.6 (clone 10-1) encoding cystic fibrosis transmembrane conductance regulator (CFTR) was used to map the bovine homolog of CFTR. Using a panel of bovine x rodent hybrid somatic cells, the homolog was mapped to bovine syntenic group U13 which corresponds to chromosome 4. CFTR is 97.7% concordant with syntenic markers T-cell receptor beta (TCRB) and P-glycoprotein 3 (PGY3). The comparative gene maps oi CFTR, TCRB, and PGY3 on human chromosome 7, bovine chromosome 4, and mouse chromosomes 5 and 6 indicate conservation of synteny, although internal rearrangements relative to HSA 7 are present in both cattle and mice.