Immune Responses in Infections with Coccidia: Macrophage Activity

Abstract

Peritoneal exudate cells from chickens immunized with two species of coccidia, Eimeria tenella or Eimeria maxima, were examined for their capacity to phagocytose stages of the parasite in vitro. True phagocytosis of the sporozoite stage is difficult to estimate because of its ability to invade cells, but may be evaluated by comparison with control suspensions. Peak activity (compared with cells from coccidia-free chickens) was found 3 to 5 weeks after the first inoulum of oocysts of E. tenella, and 1 week after the first inoculum of E. maxima-times which correspond to the onset of complete immunity to infection. Cells from coccidia-free chickens, in the presence of serum from birds immunized with E. tenella, phagocytosed sporozoites of E. tenella in a similar manner to cells from immunized birds. The immune serum had both cytophilic and opsonic adherence properties and the latter was species specific (for the two species tested).

Major histocompatibility complex control of immunity elicited by genetically engineered Eimeria tenella (Apicomplexa) antigen in chickens

“…It is not known what direct role these antibodies may have, if any, in arresting parasite development. Antigen presentation during a natural infection may involve macrophages (22) or intraepithelial lymphocytes (16). Therefore, the use of a recombinant antigen such as 5401 may invoke an additional cellular component, B cells, which may serve in some canacity to neutralize parasitism.…”

Poultry Coccidiosis: Design and Interpretation of Vaccine Studies

“…Phagocytosis by peritoneal macrophages from infected chickens was increased but varied depending on the stage and number of infections, and was enhanced by immune serum. However, it has to be stressed that peritoneal macrophages have been described to be functionally very different to tissue-resident macrophages in the gut (78), and may have a more immunomodulatory role rather than an antigen-presenting function (79). Quantification of macrophages during caecal infection with E. tenella showed higher absolute numbers in immune birds at 8 h post infection compared with naïve birds, however there was a greater increase in macrophages in naïve birds compared with immune birds (80).…”

Utility of Feed Enzymes and Yeast Derivatives in Ameliorating Deleterious Effects of Coccidiosis on Intestinal Health and Function in Broiler Chickens

“…Indeed, supplemental YCW showed commensurate growth performance and livability responses to zinc bacitracin and Salinomycin in a Eimeria and C. perfringens co-infection model (147). Chicken macrophages are involved the adaptive immune responses through interaction with Eimeria in the intestinal mucosa (148). Immunodominant surface antigens identified in E. acervulina and E. maxima have been shown to elicit measurable antibody responses with IgA being the most important isotype (131).…”