potassium-borohydride and metaperiodate

Topics: Animals; Borohydrides; Cytotoxicity, Immunologic; HLA Antigens; Humans; In Vitro Techniques; Lectins; Mice; Neoplasms; Oxidation-Reduction; Papain; Periodic Acid; T-Lymphocytes, Cytotoxic

Alloimmune murine thymus-derived cytotoxic lymphocytes (CTL) generated in vivo or in vitro are shown to lyse antigen-nonspecific target cells (tumor cells, Con A, and LPS blasts) following treatment of CTL with an oxidizing agent, sodium periodate (NaIO4). It has been shown that NaIO4 oxidizes terminal sialic acid residues of cell surface macromolecules. The presence of reactive aldehyde groups, generated by NaIO4 modification, is required for the expression of antigen-nonspecific cytotoxicity because treatment of modified cells with a reducing agent such as potassium borohydride (KBH4) resulted in the abrogation of cytotoxicity. However, KBH4 treatment of unmodified or NaIO4-modified CTL has no effect on antigen-specific cytotoxicity. The modification of CTL by NaIO4 is sufficient to lead to the formation of lymphocyte-target cell conjugates and lysis of bound targets. Monoclonal antibodies directed against the Lyt-2 antigens of CTL, but not Lyt-1 antigens, in the absence of complement inhibited the nonspecific cytotoxicity resulting from NaIO4 modification of effector lymphocytes. These findings suggest that the mere interaction with or perturbation of appropriate cell surface molecule(s) of effector lymphocytes such as Lyt antigens by receptor-ligand interaction in SCMC or by NaIO4 modification in ODCC may lead to the expression of cytotoxicity. The present studies demonstrate a functional role of surface carbohydrates on CTL in cell-to-cell recognition and interactions. Furthermore, the results suggest that target cell modification is not a requisite for recognition and lysis in an antigen-nonspecific cytotoxic system such as ODCC. However, partial blocking of ODCC by alloantibodies directed against the H-2 of unmodified target cells suggests that NaIO4-modified CTL recognize unrelated target H-2 antigens. The implication of these findings on the molecular mechanism of cell-mediated cytotoxicity is discussed.

Topics: Animals; Antigens, Ly; Ascitic Fluid; Borohydrides; Cytotoxicity, Immunologic; Epitopes; H-2 Antigens; Immunity, Cellular; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Inbred DBA; Oxidation-Reduction; Periodic Acid; T-Lymphocytes, Cytotoxic

Sialoglycoproteins of rat epididymal fluid and spermatozoa were radiolabelled by the NaIO4/KB3H4 method. At least 10 sialoglycoproteins of the epididymal fluids could be consistently demonstrated by polyacrylamide gel electrophoresis in sodium dodecyl sulphate. Two major ones (Mr 21000 and 66000) were present in the fluids of the caput and cauda epididymidis. Two (Mr 28000 and 40000) were found only in the former and two (Mr 32000 and 42000) only in the latter. There were at least 11 sialoglycoproteins bound to the epididymal spermatozoa. During epididymal transport, 8 sialoglycoproteins on the spermatozoa decreased, one (Mr 48000) remained constant and one (Mr 31000) increased in amount. During sperm maturation, some sperm-bound sialoglycoproteins, especially 3 of small molecular weights, became more resistant to the treatments with neuraminidase, trypsin and Triton X-100.

Topics: Animals; Body Fluids; Borohydrides; Electrophoresis, Polyacrylamide Gel; Epididymis; Isotope Labeling; Male; Molecular Weight; Periodic Acid; Rats; Rats, Inbred Strains; Sialoglycoproteins; Spermatozoa