Selective Platelet Immune Retention

Inbred rats were immunized with Freund's Adjuvant containing proteins of Mycobacterium tuberculosis, Mycobacterium butyrium, or dinitrochlorobenzene (DNCB). Native arterial blood was then passed over glass beads coated with those antigens. The platelet retention on the glass beads was measured.

Rats immunized with Complete Freund's Adjuvant developed accelerated platelet retention on beads coated with protein derivatives of tuberculosis (EkD) after just 18 seconds of blood flow. Rats Immunized twice maintained selective retention longer than those immnunized once. The test animals developed no cutaneous hypersensitivity nor precipitin lines on Ouchter-long gels against PPD. Rats sensitized to DNCB had accelerated platelet retention on MCB-coated beads. Results were temperature and complement dependent, and antigen-specific. Heparin caused a dose-dependent inhibition of the accelerated retention.

PYD potentiated the UP-induced aggregation of platelet-rich plasma (YW) from immunized rats.

These experiments suggest that platelets react selectively to antigens in the intravascular spaces in immune reactions.