Phagocytic funnel-like pseudopodia in lectin-treated gastropod hemocytes

Abstract

L. R. Renwrantz, T. Yoshino, T. Cheng, and K. Auld (Zoo/. Jb. Physiol. 83, l12, 1979) have described a phagocytic mechanism of Crassostrea virginica (Mollusca: Pelecypoda) hemocytes by which rat erythrocytes could be internalized through a single funnel-shaped pseudopodium. These structures were similar to those seen in vertebrate leukocytes (J. M. Orenstein and E. Shelton, Lab. Invest. 36, 363-374, 1977). This paper reports that hemocytes from two gastropods, Biomphalaria glabrata and Bulinus truncatus, will form funnel-like pseudopodia by which human erythrocytes may be phagocytosed. These pseudopodia may also form in the absence of erythrocyte-sized particles, but after treatment with a lectin. Certain lectin treatments may increase the rate of endocytosis in short-term experiments (D. A. Schoenberg and T. C. Cheng, Devel. Comp. Zmmunol., in press). and sealed with nail polish. In preparations requiring incubation with living human erythrocytes, a hypertonic CBSS (HS, 276 mosM) (D. A. Schoenberg and T. C. Cheng, lot. cit.) was substituted during lectin treatment. A 5 x 10’ cell/ml suspension of human erythrocytes in Dulbecco’s phosphate-buffered saline (DPBS, R. Dulbecco and M. Vogt, J. Exp. Med. 99, 167184, 1954) was added to the lectintreated hemocytes, and incubated for 30 min, rinsed, and incubated in DPBS for an additional 30 min. This was followed by fixation and staining.