Leukocyte populations and their cell adhesion molecules expression in newborn dromedary camel calves

Abstract

Background and Aim: Different properties of the newborn immune system have been characterized in many species. For the newborn camel calf, however, the phenotype and composition of blood leukocytes have so far not been evaluated. The current study aimed to analyze the distribution of leukocyte subpopulations and their expression pattern of cell adhesion molecules in newborn and adult dromedary camels. Materials and Methods: Blood samples were collected from 17 newborn camel calves and 32 adult camels. For each sample, total leukocytes were separated and analyzed for their composition and cell adhesion molecules expression by flow cytometry. Results: In comparison to adult camels, newborn camel calves had higher leukocyte numbers and higher numbers of neutrophils, monocytes, and lymphocytes but lower numbers of eosinophils in their blood. Among the lymphocyte populations in calves, the fractions of B cells and γδ T cells were elevated when compared to adults, whereas CD4-positive T cells were reduced. The comparison between camel calves and adult camels revealed significantly lower expression of the cell adhesion molecules CD11a, CD11b, and CD18 on granulocytes, monocytes, and lymphocytes in calves. Conclusion: Newborn camel calves show a distinct composition and phenotype pattern of blood leukocytes when compared to adult camels. The observed rise in many leukocyte populations in calf blood may be due to reduced migratory activity in calf leukocyte populations.

Recent Advances in Camel Immunology

“…As in other ruminants, camel newborns and adult camels differ significantly regarding their leukogram pattern, phenotype and functionality of blood leukocyte subpopulations ( 201 ). During their first month of life, the leukogram pattern of newborn camel calves is characterized by higher leukocyte numbers, higher numbers of neutrophils, monocytes, and lymphocytes, but lower numbers of eosinophils in comparison to adult camels ( 201 ). The reduced numbers of eosinophils in newborn camel calves, which play a major role in parasitic immunity ( 39 ), has been related to lower parasitic manifestation in comparison to adults ( 202 ).…”

“…Compared to adult camels, the fraction of B cells among blood lymphoid cells of newborn camels is higher than in adults, whereas the fraction of CD4+ T cells is lower than in adults ( 200 ). The authors discussed a link between elevated numbers of circulating leukocyte populations in camels and their lower expression density of cell adhesion molecules (CD11a, CD11b, CD18) compared to adult leukocytes ( 201 ).…”

“…The immaturity of newborn immune cells was linked to a higher susceptibility to infectious diseases and higher mortality rates during the early weeks after birth (191,(193)(194)(195)(196)(197)(198)(199)(200). As in other ruminants, camel newborns and adult camels differ significantly regarding their leukogram pattern, phenotype and functionality of blood leukocyte subpopulations (201). During their first month of life, the leukogram pattern of newborn camel calves is characterized by higher leukocyte numbers, higher numbers of neutrophils, monocytes, and lymphocytes, but lower numbers of eosinophils in comparison to adult camels (201).…”

Selected Aspects of Camel Immune System and Immune Responses

“…Expressions of the AM, CD11a, CD11b and CD18 on camel calves' leukocytes and lymphocytes were significantly lower than in adult camel cells [77]. A low AM molecule expression in newborn leukocytes could be due to a reduction in the migratory activity of the leukocyte populations [77]. Analysis of different camel lymphocyte phenotypes indicated that 83% are naïve CD4 + CD11a and CD44, whereas 13% of the lymphocytes are effector cells with CD4 + , CD11a and CD44 hi [76].…”

“…However, in the last decade major efforts have led to the identification of several important markers, especially that of the Analysis of the CD markers on the camel lymphocytes in the peripheral blood of newborn camels indicated a higher expression of γδ cells and B cells than in adult camels, whereas the expression of the CD4 + T-helper cells in camel calves was less than in adult camels [77]. Expressions of the AM, CD11a, CD11b and CD18 on camel calves' leukocytes and lymphocytes were significantly lower than in adult camel cells [77]. A low AM molecule expression in newborn leukocytes could be due to a reduction in the migratory activity of the leukocyte populations [77].…”