Intestinal response of sheep to intraperitoneal immunization

Area of Science:

• Immunology
• Gastroenterology

Background:

• The IgA immune system plays a crucial role in mucosal immunity.
• Stimulating IgA production in the gut is essential for preventing enteric infections.

Purpose of the Study:

• To develop an immunization method for centrally stimulating the IgA immune system in sheep.
• To assess the release of IgA antibody-containing cells (ACC) into intestinal lymph following immunization.

Main Methods:

• Sheep were immunized intraperitoneally with ovalbumin.
• Intestinal lymph was collected to quantify antibody-containing cells (ACC) of different immunoglobulin classes (IgA, IgM, IgG1).
• Comparison with intraduodenal infusion in antigen-primed rats.

Main Results:

• Intraperitoneal ovalbumin injection led to a significant output of IgA ACC in intestinal lymph, peaking at 8-9 days.
• At peak response, IgA ACC constituted 1.4% of lymph cells, with IgM and IgG1 ACC at 3.5% and 2.9%, respectively.
• Intraduodenal ovalbumin infusion in primed sheep did not induce ACC in intestinal lymph, unlike in rats.

Conclusions:

• Intraperitoneal immunization is an effective strategy to stimulate IgA antibody-containing cell release into sheep intestinal lymph.
• This method offers a potential avenue for enhancing mucosal immunity in the gastrointestinal tract.
• Sheep immune responses differ from rats regarding IgA induction via intraduodenal routes.