Abstract:
There are often outbreaks of infectious diseases on farms, which not only disrupt production but
also cause significant economic losses. Vaccines are given to prevent the spread of these infectious
diseases, but they produce only systemic antibodies or antibodies in the mucosa of a particular
system. So, a new mucosal vaccination route is needed where the vaccine will produce antibodies
in the systemic circulation as well as in the mucosa of many systems. In our study, the cloaca was
targeted because it is associated with the mucosa of many systems. Whole-mount and routine
histological staining show both lymphatic nodules and diffuse lymphatic tissues in the lamina
propria of cloaca. These lymphatic tissues are made up of Bu-1+ B-cells, CD3
T-cells, and
KUL01+ macrophages and monocytes. So, this is a new mucosa-associated lymphoid tissue,
named cloaca-associated lymphoid tissue (CALT). The CALT contains antigen-presenting cells
(dendritic cells, macrophages, B cells, MHC II molecules, and T cells) and is equipped with blood
vessels and high endothelial venules, which indicate its functional status. More antibodies were
produced in the treatment group compared to the vehicle control group after administration of
the infectious bursal disease (IBD) and the Newcastle disease (ND) vaccine through cloaca. In
addition, the cloaca-associated route produces a higher number of antibodies than the other
traditional routes, which reveals the uniqueness of this route. Cloacal-vaccinated chickens
showed less damage to the follicle and epithelium of the bursa of Fabricius compared to other
groups, indicating its lower cytotoxic effect. Therefore, the cloaca-associated mucosal vaccination
route produces more antibodies than other mucosal vaccination routes, which will protect the
chickens on the farm to a greater extent.
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