The Distribution of SIgA and IgG Antibody-Secreting Cells in the Small Intestine of Bactrian Camels (Camelus bactrianus) of Different Ages

Abstract

Secretory immunoglobulin A (SIgA) and immunoglobulin G (IgG) antibody-secreting cells (ASCs) are two important cell types in the mucosal immune system. This study aimed to explore the distribution of these ASC populations in the small intestine of Bactrian camels of different ages. Twenty-four Alashan Bactrian camels were divided into the following four age groups: young (1–2 years), pubertal (3–5 years), middle-aged (6–16 years) and old (17–20 years). SIgA and IgG ASCs in the intestinal mucosa lamina propria (LP) were observed and analyzed using immunohistochemcal techniques. The results from all age groups show that both SIgA and IgG ASCs were diffusely distributed in the intestinal LP, and some cells aggregated around the crypts. Moreover, the densities of the two ASC populations gradually increased from the duodenum to the jejunum and then decreased in the ileum. Meanwhile, there were more SIgA ASCs than IgG ASCs in the duodenum, jejunum, and ileum, and these differences were significant in the young and pubertal groups (P<0.05). In addition, the SIgA and IgG ASC densities increased from the young to the pubertal period, peaked at puberty, and then gradually decreased with age. The results demonstrate that the SIgA and IgG ASC distributions help to form two immunoglobulin barriers in the intestinal mucosa to provide full protection, helping to maintain homeostasis. These findings also underscore the importance of researching the development and degeneration of intestinal mucosal immunity in Bactrian camels.

Recent Advances in Camel Immunology

“…Mucosal immunoglobulins contribute to the immune homeostasis at the mucosal interface ( 216 ). The distribution of secretory IgA (SIgA) and IgG-secreting cells (ISCs) in the lamina propria of the small intestine of Bactrian camels suggests their significant contribution to mucosal immunity in this species ( 210 , 217 ). Similar to the age-related changes in the number of PP in the intestine of Bactrian camels, SIgA and IgG ISC numbers increase with age with a peak at puberty ( 210 , 217 ).…”

Age‐related changes in the morphology and the distribution of IgA and IgG in the pharyngeal tonsils of yaks (Bos grunniens)

“…When IgA‐mediated mucosal elimination of antigens is unsuccessful, such as when the first‐line immunologic barrier is destroyed, IgG, with its proinflammatory activity, can rapidly recruit phagocytic innate immune cells through the activation of an inflammatory reaction, helping to eliminate invading pathogens (Sylvestre & Ravetch, ; Ogra, ; Cerutti, et al, ). In recent years, the expression and distribution characteristics of IgA and IgG were mainly reported in the palatine and pharyngeal tonsils of cattle ( Bos taurus ) (Manesse et al, ; Yasuda, et al, ), the pharyngeal tonsils of human ( Homo sapiens; Ishikawa, Wicher, & Arbesman, ; Boyaka et al, ), the respiratory tract of pig (Li, Liu, Gao, Yu, & Yang, ), and the palatine tonsil and small intestine of the Bactrian camel (Jia et al, ; Zhang, et al, ).…”

Selected Aspects of Camel Immune System and Immune Responses

“…However, bovine CDR3 is known for its ultralong subset, which ranges from 50 to 60 amino acids [44]. [46]. It has been clearly indicated that aging has a significant impact on the density and distribution of IgA + and IgG + cells [45].…”

“…The scattered distribution of the IgG and IgA ASCs in the small intestine is of significant importance for providing full-protection and immune surveillance of the mucosal immune homeostasis and intestinal integrity [45] [46]. The densities of IgA ASCs are great-er than IgG ASCs in the duodenum, jejunum and ileum of young and pubertal camels [46].…”

“…Distribution of the Camel IgA + and IgG + CellsStudies on the tissue distribution of different camel antibody classes and subclasses are scant. A few studies on the antibody isotypes and antibody secretory cells distribution were recorded[45] [46]. The B-lymphocytes that express IgA + and IgG + cells are diffusely distributed in the non-subepithelial area of the lamina propria (LP) of the aggregated lymphoid nodules area (ALNA), and few are in the subepithelial dome (SED) of the camel intestine[45] [46].…”