Effect of trypsinization on lectin binding to germ cells from ICR and T/t6 mice

Immunomodulatory capacity of fungal proteins on the cytokine production of human peripheral blood mononuclear cells

Immunomodulation by fungal compounds can be determined by the capacity of the compounds to influence the cytokine production by human peripheral blood mononuclear cells (hPBMC). These activities include mitogenicity, stimulation and activation of immune effector cells. Eight mushroom strains (Agaricus blazei, Coprinus comatus, Flammulina velutipes, Ganoderma lucidum, Grifola frondosa, Volvariella volvacea, Lentinus edodes, and Pleurotus ostreatus) were tested for the immunomodulating activity of the isolated protein fractions and polysaccharides fractions present in mycelia and culture liquid. The fungal proteins and polysaccharides have been investigated for their in vitro effect on the cytokine profile (IFN-gamma, IL-4, IL-10, IL-12 and TNF-alpha) of unstimulated or hPBMC stimulated with the polyclonal stimulations PMA/Ca-I, ConA or LPS. In addition to their influence on the cytokine profile, the hemagglutination activity of the fungal proteins on rabbit red blood cells was determined. Proteins from V. volvacea and G. lucidum showed immunomodulating activity without the presence of any mitogen, however, neither of them decreased the production of IL-4 and IFN-gamma in combination with a stimulus. All used stimuli resulted in an induction of IL-12 in the presence of the protein extracts, suggesting a direct effect on monocytes. This effect might lead to the indirect immunomodulation of T cell activation and cytokine production. In addition, both protein extracts showed more hemagglutination activity after trypsin treatment of the rabbit red blood cells, indicating the presence of carbohydrate-binding proteins, like lectins and FIPs. In conclusion, the protein extracts of V. volvacea and G. lucidum contain immunomodulating activity by acting directly on monocytes and thereby modulating T cell activation. Further purification of the fungal extracts is needed to clarify whether there are FIPs or lectins present that are responsible for this immunomodulating activity.

Changes in lectin binding patterns of mouse male germ cells (gonocytes) during prespermatogenesis

The distribution of sugar residues in gonocytes of the differentiating mouse testis was examined by light microscopy using 22 different kinds of lectins. Characteristic binding patterns of sWGA, VVA, and LEA in gonocytes were observed during prespermatogenesis. sWGA preferentially bound to the cytoplasm and plasma membrane of gonocytes on 16.5 days post coitus (dpc). Its reaction decreased thereafter and almost disappeared on 1.5 days post partum (dpp), but reaction reappeared on 4.5 dpp and continued until 6.5 dpp. The VVA reaction was recognized in a few gonocytes on 0.5 dpp, and remained strong until 6.5 dpp. LEA reacted strongly in the plasma membrane and cytoplasm of gonocytes from 0.5 dpp to 6.5 dpp. The present study indicates that sWGA, VVA, and LEA are useful markers for gonocytes, and the appearance or disappearance of sWGA and VVA may be related to the differentiation of gonocytes during prespermatogenesis.

A monoclonal antibody recognizing a differentiation marker on rat gonocytes

Monoclonal antibodies (MAb) were raised against a testicular membrane fraction from 18-day post coitum (p.c.) rat testes. One antibody, designated 4B6.3E10 (mu, kappa), was obtained which specifically reacted with gonocytes in the fetal testis. No significant cross-reactivity with other tissues from the 18-day p.c. embryo was found. MAb 4B6.3E10 was reactive with rat gonocytes from 17-day p.c. until the day of birth. Germ cells at later stages of testis development did not show any labelling. The epitope recognized by 4B6.3E10 is a carbohydrate as periodate treatment leads to a loss of reactivity of the antibody. By SDS-PAGE and Western blotting of proteins extracted from a testicular membrane fraction from 18-day p.c. testes, MAb 4B6.3E10 was found to recognize at least 3 protein moieties with apparent molecular weights in the ranges of 80-100, 120, 160-180 kDa (either under reducing- or non-reducing conditions). The results suggest that MAb 4B6.3E10 recognizes a specific differentiation marker for fetal rat gonocytes.