Third component of complement, immunoglobulin deposition, and leucocyte attachment related to surface sulfate on larval Taenia taeniaeformis.

Cysticerci and strobilocerci of Taenia taeniaeformis were incubated with leucocytes from peritoneal washings of normal and T. taeniaeformis-infected rats in the presence of either normal sera or sera from infected rats. Leucocytes from infected and normal rats attached exclusively to the scolices but not the bladders of the larvae in the presence of serum from normal or infected rats. Heat inactivation at 56 C for 30 min destroyed the serum-mediated cell attachment. Histochemical staining of the larval taeniids with acid Alcian Blue demonstrated high concentrations of sulfated mucopolysaccharides on bladders that were not present on scolices. Immunofluorescent staining detected no difference in IgG deposition on the surfaces of bladders and scolices after incubation with rat sera in contrast to the markedly greater amounts of complement protein C3 found on scolices versus bladders. These results indicate that polysulfated substances on the bladder of this larval taeniid are associated with regional resistance to C3 deposition and leucocyte attachment.