A histological, lectin and S-100 histochemical study of the developing prenatal human sublingual salivary gland.

Lectin and S-100 protein histochemistry during fetal growth and development (10-38th gestational weeks) of these glands was studied. The histological development of glandular structures followed the known pattern for other salivary glands. Using biotinylated lectins Ulex europeus-I, Dolichos biflorus, Glycine maximus (soyabean), Helix pomatia, Arachis hypogaea (peanut) and Triticum vulgare (wheatgerm), the binding level and, by implication, the concentration of associated specific oligosaccharide available for binding was low at 10 to 19 weeks and generally higher as maturity increased through the middle and late stages of development. S-100 protein reactivity was demonstrated in the cytoplasm of basophil acinar cells of the gland primordia from their origin. Stereological analysis of these developing salivary glands showed a highly significant progressive increase in proportional gland volume occupied by acini from 25% at 20 weeks to 60% at 38 weeks (p < 0.0001), and a comparable halving of the relative gland volume occupied by connective tissue in the same period (p < 0.0001). The extent of these changes depended upon the stage of differentiation and maturation of the glands but by the late stage of fetal development, histochemical reactions were similar to known adult patterns.