Immune hematology

The researches find that the Multiple types of immune cells are interspersed among the epithelial cells lining the intestines and are considered to be a first line of defense against pathogens. Therefore The survival and interaction of these intraepithelial lymphocytes and their roles in intestinal inflammation are not well understood. Ali Nazmi, Ph.D., Danyvid Olivares-Villagómez, Ph.D., and colleagues have examined the effect of one type of intraepithelial lymphocyte ;(iCD8alpha) on another (ILC1-like).

Multiple types of immune cells

Using mice with reduced numbers of iCD8alpha cells, they found that these cells play a critical role in the survival of ILC1-like cells; and that this effect is partly mediate by the factor osteopontin. In a mouse model of intestinal inflammation that involves ILC1-like cells; reduced iCD8alpha cell numbers resulted in milder inflammation and treatment with osteopontin increased disease severity.

The findings; reported in PLOS ONE; implicate iCD8alpha cells in ILC1-like cell survival and intestinal inflammation and add to the growing roles of osteopontin in various biological processes. Intestinal intraepithelial lymphocytes (IEL) constitute a population of cells dwelling interspersed in the monolayer of intestinal epithelial cells (IEC); and represent a unique immunological compartment in the intestines. Because of their anatomical location; IEL are consider to be the first line of defense against the enormous antigenic stimulus present in the lumen of the intestines.

Intestinal intraepithelial lymphocytes

T cell receptor αβ+ and γδ+ cells constitute the great majority of IEL, and these cells possess many and varied roles during mucosal immune responses and inflammatory processes; ranging from specific immunity against pathogens; tissue repair and homeostasis of the intestinal epithelium. Lately; it has been recognize that the IEL compartment also harbors TCRneg lymphoid cells with critical roles in mucosal immune responses.

The great majority of TCRneg IEL is compose of cells expressing intracellular CD3γ; which can be divide in CD8αα+ or CD8αα IEL. TCRnegCD8αα+ IEL, also refer to as innate CD8α (iCD8α) cells; have been previously characterize by our group both in mice and humans. iCD8α cells possess a chemokine and cytokine signature; antigen processing capabilities, and other functions such as bacteria uptake, that suggest that these cells are important during early immune responses. Other TCRneg IEL resemble innate lymphoid cells (ILC) with differential expression of the natural cytotoxicity receptor NKp46. Although their function is not completely understand; NKp46+NK1.1+ IEL have been shows to promote disease development in the anti-CD40 model of colitis.