HLA molecule--cytoskeleton associations induced by cross-linking with specific antibodies

Sera of patients with antibodies against HLA-typed panel, control human sera, anti-beta 2-microglobulin monoclonal antibody recognizing HLA class I molecules, anti-HLA class II monoclonal antibodies and control antibodies were used in indirect immunofluorescence study of living human peripheral blood lymphocytes and their cytoskeletons. Lymphocytes immobilized on concanavalin A-precoated glass slides enabling extraction procedures and repeated washings were found useful for such a study. If the lymphocytes were treated with human polyclonal anti-HLA antibodies only, or with two antibodies (i.e. with a specific monoclonal anti-HLA antibody and an anti-mouse Ig polyclonal antibody labelled with fluorescein isothiocyanate (FITC), the cross-linking of the surface molecules caused their resistance to the detergent effect. Murine monoclonal anti-HLA antibodies alone, bound to the cell surface molecules, formed immune complexes easily extracted with Triton solution. In such cases, the second anti-mouse Ig antibody labelled with FITC did not visualize specific molecules in the remaining matrix. No significant changes in the microtubules of cells treated with anti-HLA antibodies were observed.