RESUMO
Diversification of the primary antibody repertoire occurs in young rabbit appendix. As a prelude to molecular investigation of whether human appendix has a similar role, we compared the lymphoid morphology and distribution of common B- and T-cell subsets in frozen and/or paraffin-embedded normal appendix specimens at various ages. IgA, IgM and IgG staining patterns were similar in frozen human and rabbit appendices. The elongated follicles of the young human and rabbit appendices regressed with age to resemble Peyer's patches. Although similar in morphology to the bursa, human and rabbit appendix follicles differ in that they do not involute completely with age and contain significant numbers of germinal center (GC) T cells although the number is low early in life. If the human appendix functions as a primary lymphoid organ, it may occur during the first few months of age when the GC T-cell density is low.
Assuntos
Antígenos CD , Apêndice/imunologia , Bolsa de Fabricius/imunologia , Tecido Linfoide/imunologia , ADP-Ribosil Ciclase , ADP-Ribosil Ciclase 1 , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Animais , Antígenos de Diferenciação/análise , Linfócitos B/imunologia , Antígenos CD4/análise , Antígenos CD8/análise , Galinhas , Criança , Pré-Escolar , Centro Germinativo/imunologia , Humanos , Imunoglobulinas/análise , Imuno-Histoquímica , Lactente , Recém-Nascido , Antígeno Ki-67/análise , Contagem de Linfócitos , Tecido Linfoide/crescimento & desenvolvimento , Glicoproteínas de Membrana , Pessoa de Meia-Idade , NAD+ Nucleosidase/análise , Coelhos , Linfócitos T/imunologia , Triexosilceramidas/análiseRESUMO
We compared the effects of neonatal appendectomy in rabbits on total Ig and antigen (Ag)-specific Ig levels in the serum and gut, and on plasma cell numbers in the small intestine in response to intraperitoneal (i.p.) and intraduodenal (i.d.) immunizations with ovalbumin (OVA). Animals were sacrificed after 9 weeks. Antibodies (Abs) in the duodenum were collected and quantified by enzyme-linked immunosorbent assay (ELISA) while plasma cells were quantified by double immunofluorescent staining. Appendectomy markedly reduced total intestinal IgA (P < 0.0006), IgM (P < 0.003), and IgG (P < 0.05) relative to controls, whereas total serum Ig levels were not lowered significantly. Moreover, appendectomy nearly ablated OVA-specific IgA (P < 0.007) in the gut and severely depleted OVA-specific IgG in the gut (P < 0.03) and serum (P < 0.007). The sharp decreases in total IgA and anti-OVA IgA were paralleled by decreases in total IgA+ plasma cells (P < 0.0005) and OVA-reactive IgA+ plasma cells (P < 0.05). These results support a major role of the rabbit appendix in seeding the intestinal lamina propria with plasma cell precursors, especially those producing IgA.
