title: Age-related refractoriness of PHA-induced lymphocyte transformation. II. 125-I-PHA binding to spleen cells from young and old mice.
abstract: Using 125-I-labelled red kidney bean phytohemagglutinin (125-I-PHA), we have found that spleen cells from old BC3F1 mice bind this plant mitogen equally well, if not better, than spleen cells from young BC3F1 mice, although PHA-induced blastogenesis of spleen cells from old mice is sharply reduced. Analyes demonstrated that there is neither significant alteration of binding affinity nor decreased total number of membrane receptor sites for PHA in senescing mouse spleen cells. The amount of PHA which was initially bound to spleen cells in serum-free medium appeared to be insufficient for a subsequent full stimulation of blastogenesis ([3-H]thymidine incorporation) in either young or old mouse spleen cells; when washed free of unbound extracellular PHA and upon clutivation in serum-containing culture medium, spleen cells rapidly released more than 90% of the bound PHA. Also, temperatures which change cell membrane morphology played a significant role in the binding and retention of PHA. However, no difference was observed between young and old mouse spleen cells in all these phenomena of PHA-cell membrane interaction.
mesh_terms: D000375:Aging; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D037102:Lectins / Q000378:metabolism / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008934:Mitogens / Q000378:metabolism; D011485:Protein Binding; D013154:Spleen / Q000276:immunology*; D013960:Thyroid Function Tests
chemical_list: D037102:Lectins; D008934:Mitogens