Differential Expression and Localization of Cd300a and Tryptase in Salivary Glands and Oral Mucosa: An Immunohistochemical Study

Purpose: Cd300a and tryptase are two molecules of interest in immunological and pathological studies. Cd300a is an in- hibitory receptor found primarily on myeloid cells, including mast cells, macrophages, and dendritic cells, where it plays a role in modulating immune responses. Tryptase, on the other hand, is a serine protease predominantly stored in mast cell granules and is involved in processes such as inflammation, tissue remodeling, and host defense mechanisms. In our study, we are investigating the expression of Cd300a and tryptase in various cases involving major and minor salivary glands as well as oral mucosa. Methods: Utilizing immunohistochemistry and double im- munof luorescence techniques with antibodies sourced from Abcam, we assessed the presence of these molecules in differ- ent tissue pathological and normal structures. Results: Our findings indicated that tryptase exhibited positivity in various epithelial structures, notably within the salivary gland ducts, particularly the striated ducts, while acini (adenomers) were negative. Additionally, endothelial cells were tryptase positive but Cd300a negative. Tissue infiltrates dis- played cells that were positive for both tryptase and Cd300a. The results of our study suggest a distinct localization and functional implication of tryptase within the epithelial and endothelial compartments of salivary glands, whereas. Cd300a appears to be more involved in immune cell regulation within infiltrates. Conclusion: These findings contribute to a better under- standing of the differential roles of tryptase and Cd300a in salivary gland and oral mucosal biology, potentially informing future therapeutic strategies targeting these molecules in re- lated pathologies.