PROBLEM: Immunosuppressive fraction of boar seminal vesicle fluid (ISF) was
tested to muffle primary and secondary antibody responses to xenotranfusio
ns. Contemporaneously, heparin non-binding fraction of seminal plasma (H- f
raction), presumed to be identical to ISF, was used to support the results.
METHOD: To study their similarity, ISF and H- fraction were analyzed by hig
h-performance liquid chromatography and the separated proteins by N-termina
l sequencing. In sera of mice treated with ISF or H- fraction, the producti
ons of antibodies against rat erythrocytes and blood serum were evaluated b
y enzyme-linked immunosorbent assay (ELISA). The productions of IgM, IgA, a
nd IgG subclasses were followed by sandwich ELISA.
RESULTS: ISF and H- fraction were proved to be equal complexes of porcine s
eminal plasma (PSP) proteins PSP I and PSP II. Both inhibited antibody resp
onses to rat erythrocytes and serum and the concentrations of IgM, IgG, IgG
, and IgG, after the first transfusion with a long-lasting effect. Both sup
pressed the secondary antibody production if applied before the second tran
sfusion. IgA and IgG, stayed uninfluenced. ISF and H- fraction had an equal
CONCLUSIONS: ISF was characterized biochemically, found to be identical to
H- fraction, and determined to be powerful in overcoming unwanted exaggerat
ed antibody responses to xenotransfusion.