B cell differentiation in the bursa of Fabricius and spleen of embryos and chicks immediately after hatching

Abstract

Flow cytometric analysis and immunohistochemical observation were used to qualitatively and quantitatively clarify the nature of B cell differentiation in the bursa of Fabricius of chick embryos and to determine the timing of antibody class switching in chicken spleens based on positivity of IgM and IgG on and in the cells. In the bursa, the sIgM-positive cell population formed from the 12(th) to 15(th) day of embryogenesis. The proportion of sIgM-high expressing (sIgM(high)) cells was lower among bursacytes than splenocytes of hatched chicks, suggesting that the sIgM(high) bursacytes are to be released to peripheral sites. The proportion of sIgM(high) cells was higher at 0 days old than at any other examined stage of development. Colonization of the spleen by B cells occurred between the 18(th) day of embryogenesis and 0 days old. Antibody class switching was thought to start in the spleen between 1 and 2 weeks of age, because IgG-positive cells were present in the spleen of 2-week-old chicks, but not 0-day-old or 1-week-old chicks.

The influence of antibiotics on B-cell number, percentage, and distribution in the bursa of Fabricius of newly hatched chicks

“…Between d 9e to 10e and 16e, the rearrangement of Ig genes takes place by somatic recombination (Benatar et al, 1992;Ratcliffe, 2006;Reynaud et al, 1992). At this time, secretory (s)IgM is already observed on the surface of B cells (Narabara et al, 2009). The second phase begins shortly after hatching and occurs until 2 to 4 wk of age.…”

New Insight into the Structure, Development, Functions and Popular Disorders of Bursa Fabricii

“…There are two types of immunoglobulin‐containing cells in the medulla: IgM‐ and IgG‐positive cells. IgM‐containing cells are typical B cells that begin to biosynthesize IgM in the bursa between E12 and E15 (Otsubo et al, ; Narabara et al., ). By contrast, IgG‐containing cells are reticular cells (or BSDC) that capture aggregated IgG on their surface (Ekino et al., ).…”