HD5 mAb blocks interaction of B27₂ to leukocytes and modulates activation of CD4+ T-cells by B27₂.

<p><b>(A)</b> B27_<b>2</b> (1x)-tetramers were shown to bind to CD4+ T-cells, B-cells (CD45RA,-lineage) and NK (CD161a,-lineage) populations. Pre-incubation of HD5 or HC10 with B27_<b>2</b>(1x)-tetramers partially blocked interactions with cells when compared to control antibodies (W6/32 and isotype). <b>(B)</b> Tg and WT CD4+ T-cells produce TNF after incubation with B27_<b>2</b> (1x)-tetramers. Pre-incubation of HD5 or HC10 with B27_<b>2</b> (1x)-tetramers inhibited the interaction to CD4+ T-cells and the production of TNF. <b>(C)</b> Tg and WT CD4+ T-cells produce TNF after incubation with .220 B27cells expressing B27_<b>2</b> dimers, but not with .220 and .220 B7 cells. Pre-incubation of HD5 or HC10 with .220 B27 cells blocked the interaction of B27_<b>2</b> to CD4+ T-cells and the production of TNF. Representative flow cytometry plots belong to leukocytes populations of Tg rats. Tests were performed in triplicates. Tet = tetramer. Values are expressed as mean±SEM. *p<0.05, **p<0.01, as determined by one-way ANOVA followed by Bonferroni post-hoc analysis.