Both quantitative and qualitative estimations of the basidiomycetes Grifola frondosa and Lentinus edodes (shiitake mushroom) lectins binding to   the specific and non-specific polyclonal rabbit antibodies were attempted. The G. frondosa lectin complexation with homological antibodies was shown to be characterized by greater binding constants as compared to non-homological antibodies. Therewith the values of changes in standard free energy ∆G⁰ displaying a strength of both complexes were essentially the same. As for the two extracellular L. edodes lectins, L1 and L2, the anti-lectin L1 antibodies bound crude L2 with ten-fold-greater ELISA results compared to crude L1, but showed only limited reaction with L2 in the course of this lectin purification. The data obtained testify to universality of biospecific reactions “antigen-antibody” and “lectin-carbohydrate” at a molecular level, and could give new insight into the phenomenon of these biospecific interactions. Obviously, the actual specificity in the above processes of bio-recognition should be discussed in the especial case of the lectins and antibodies incorporation into a living system.