Intraepithelial plasma cells in the avian copulatory organ of two tinamou species: quantitative variation during the breeding season

Abstract

A recent observation concerning the phallus of the tinamou Nothura maculosa was the presence of cells resembling plasma cells within the epithelium of the fixed tubular portion. Owing to this unusual location of plasma cells, we studied the phalli of the tinamous N. maculosa and Rhynchotus rufescens to confirm the occurrence of intraepithelial plasma cells and to evaluate the seasonal variation in these cells. Abundant plasma cells were found within the epithelium of the fixed tubular portion of the phallus but not in the evertible portion. Migration of plasma cells from the adjacent connective tissue through the basement membrane and between the epithelial cells was frequent. Some plasma cells exhibited a rough endoplasmic reticulum with variable cisternal distension, containing fine, slightly electron-dense, granular material suggestive of immunoglobulin accumulation. An expressive increase of more than 800% in the number of intraepithelial plasma cells was found during the breeding season compared to the non-breeding season. By establishing the occurrence of intraepithelial plasma cells in the phallus and their seasonal variation, the results contribute to a better understanding of the role of these cells in the mucosal immune system of the reproductive tract of male birds.

The origin of prostate gland-secreted IgA and IgG

“…We have shown an increased number of CD45RA + /IgA + and CD45RA + /IgG + plasma cells in the epithelial layer. Secretory plasma cells have been found in the epithelial layer of the avian oviduct 24 , 25 ; however, this is the first time that plasma cells have been observed within the epithelial layer in a mammalian gland. It is not clear, at this time, whether these cells are in transit (as suggested for the avian oviduct), or if they reside transiently or permanently in the prostate epithelial layers.…”