Monoclonal antibodies to the secretory granule membrane of the rabbit parotid gland: Presence of a common antigen in secretory granules of both exocrine and endocrine cells.

Monoclonal antibody to a common antigen of secretory granule membranes: intracellular localization and recycling of the antigen after secretion.

“…We recently prepared MAb to secretory granule membranes of the rabbit parotid gland and demonstrated the presence of the common antigen of secretory granule membranes, secretory granule specific antigen (SGSA). in the rabbit (45). The MAb to rat and rabbit secretory granule membranes displayed a positive immunoreaction only in the respective animals and yielded no crossreaction to other animals.…”

“…The MAb to rat and rabbit secretory granule membranes displayed a positive immunoreaction only in the respective animals and yielded no crossreaction to other animals. However, the nature of the common antigens in the secretory granules may well be conserved among animals, since the characteristics of the SG 170 antigen are almost identical to those of SGSA in the rabbit (45). Both these antigens were integral membrane glycoproteins with N-linked carbohydrate and were localized on the luminal side of secretory granules.…”

“…The method of MAb production has been described previously (38,45). In short, 6-week-old female Balb/c mice were subcutaneously immunized with the secretory granule membrane (100 pg protein) with complete Freund's adjuvant, and with incomplete Freund's adjuvant 2 weeks later.…”

“…Two-phase Fractionation of the Antigen. Proteins of intact secretory granules of rat parotid gland were fractionated in Triton X-114 according to the method of Bordier (5,45).…”

“…Intact secretory granules were treated with trypsin in the presence or absence of 0.3% Triton X-100 to investigate the orientation of the antigen on the secretory granule membrane, as described previously (45).…”