Marsupial immunoglobulins: an immunoglobulin molecule resembling eutherian IgA in serum and secretions of Setonix brachyurus (quokka)
Bell, R.G.; Stephens, C.J.; Turner, K.J.
Journal of Immunology 113(1): 371-378
1974
ISSN/ISBN: 0022-1767 PMID: 4134066 Document Number: 74692
An immunoglobulin class present in several external secretions and serum of the quokka is described. This immunoglobulin possesses antibody activity and shares light chain determinants with other serum immunoglobulin classes but has heavy chain antigenic determinants which are exclusive to this class. In milk the mol. wt. exceeds 200 000 and in serum a bi-modal distribution suggests 2 separate mol. wt forms, one of >200 000 and another of approx. 150 000. Local challenge of the mammary gland in lactating quokkas induced an antibody response in milk which was restricted to this class. The immunoglobulin was designated IgA by virtue of its biological and physicochemical characteristics which were analogous to those of eutherian IgA.