Effects of tunicamycin on insect cells.

Conclusions Use of the drug tunicamycin has greatly facilitated study of many different aspects of immunoglobulin biosynthesis. The most striking conclusion is that blocking glycosylation does not prevent synthesis of immunoglobulin heavy chains either directly or by feedback; non-glycosylated heavy chains are able to assemble into immunoglobulin molecules capable of being secreted. Since glycosylation affects overall protein threedimensional structure, differences in the structure of nonglycosylated immunoglobulins might be responsible for the failure of non-glycosylated IgM to be transferred to the cell surface, alterations in the details of assembly and secretion of the non-glycosylated immunoglobulins. Such changes in structure in the non-glycosylated molecules might also affect function, and studies on the function of non-glycosylated antibodies should prove rewarding.