SURFACTANT PROTEINS A (SP-A) AND D (SP-D) - LEVELS IN HUMAN AMNIOTIC-FLUID AND LOCALIZATION IN THE FETAL MEMBRANES

Surfactant proteins A (SP-A) and D (SP-D) are major proteins, in the l ung, which are composed of collagenous and globular domains. They show an overall similarity to the serum complement protein Clq, which is i nvolved in the initiation of antibody-dependent defence mechanisms. Bo th SP-A and SP-D were detected, immunochemically, in amniotic fluid as early as 26 weeks gestation and, as expected, SP-A levels rose sharpl y from 32 weeks towards term. By contrast, SP-D levels in the same sam ples rose only moderately. Immunochemistry of paraffin sections of fet al membranes, revealed the presence of both SP-A and SP-D in the amnio tic epithelium and chorio-decidual layers. SP-A and SP-D are both lect ins and therefore they may play a role in the antibody-independent rec ogniton and clearance of pathogens in the amniotic fluid.