Lectin binding studies on murine peritoneal cells: Physicochemical characterization of the binding of lectins from Datura stramonium, Evonymus europaea, and Griffonia simplicifolia to murine peritoneal cells

Abstract

Purified 125I-labeled lectins from Datura stramonium, Evonymus europaea, and Griffonia simplicifolia (I-B4 isolectin) were used to analyze changes in the expression of carbohydrates on the surface of resident (PC) and thioglycollate-stimulated murine (C57B/6J) peritoneal exudate cells (PEC). The lectins from D. stramonium, E. europaea, and G. simplicifolia I-B4 bind specifically to PEC with relatively high affinity (Kd = 5.65 +/- 1.08 x 10-7 m, 1.08 +/- 0.12 x 10-8 m, and 1.33 +/- 0.15 x 10-7 m, respectively). Assuming a single lectin molecule binds to each cell surface saccharide, the number of receptor sites per cell ranged for different cell samples from 22.3 to 50.0 x 106, from 3.8 to 4.8 x 106, and from 2.0 to 16.8 x 106 for D. stramonium, E. europaea, and G. simplicifolia I-B4 lectins, respectively. There were approximately 3- to 7-fold, 16- to 20-fold, and 2-to 20-fold increases in binding capacity for D. stramonium, E. europaea and G. simplicifolia I-B4, respectively, compared to the binding to resident, peritoneal cells. Scatchard plots of the binding of all three lectins to PEC were linear, suggesting that the receptor sites for these lectins are homogeneous and noninteracting. The binding capacity of these lectins to PEC was unchanged after trypsin digestion of cells. The expression of carbohydrates on the surface of PEC was also monitored by an agglutination assay. PEC were agglutinated by all three lectins whereas PC either were not agglutinated or were agglutinated only at high lectin concentrations. On the basis of our knowledge of the carbohydrate binding specificity of the D. stramonium and G. simplicifolia I-B4 lectins, we postulate that, parallel with thioglycolate stimulation, there is an increase in the number of N-acetyllactosamine residues and terminal [alpha]--galactosyl end groups. The blood group B, and H type 1 determinants--Ga1[alpha]1,3[Fuc[alpha]1,2]Ga1[beta]1,3(or 4)GlcNAc and Fuc[alpha]1,2Ga1[beta]1,3G1cNAc, respectively, as well as Ga1[alpha]1,3Ga1[beta]1,3(or 4)GlcNAc--may be considered to be possible receptors for the E. europaea lectin. These glycoconjugates, present on the surface of peritoneal exudate cells, provide new chemical markers for studying the differentiation of resident peritoneal cells.