Submitted to: Science
Publication Type: Other
Publication Acceptance Date: October 8, 1995
Publication Date: N/A
Interpretive Summary: The immune system of all animals (including humans) is asked to continually monitor our body's tissues for the presence of foreign organisms. As a result, our white blood cells are continually recruited from blood into tissues to combat infections caused by pathogens and normal flora. Our research on dairy cattle afflicted with a genetic defect in the movement of cells from blood into tissues (bovine leukocyte adhesion deficiency, BLAD) led us to observe that white blood cell populations (especially neutrophils) are produced in large quantities on a daily basis in response to normal flora present at body surfaces. Independent researchers had reported a different, but related, genetic defect in mice where a build-up of neutrophils in blood was observed (similar to what we observe with BLAD cattle). The significance of this report was that we offered an alternative interpretation of their findings; that normal flora continually recruit neutrophils into tissues and that any defect in the recruitment process will lead to a build-up of neutrophils and other leukocytes in the blood stream. This interpretation of normal immune function may reemphasize the role of neutrophils in health maintenance.
Technical Abstract: Cacalano et al. describe neutrophil and B-cell expansion in mice lacking the murine interleukin-8 receptor homolog (mIL-8Rh). Neutrophils from these mice did not migrate toward ligands of the mIL- 8Rh, and many fewer neutrophils arrived at sites of inflammation. These results could be expected, but the profound increase in the neutrophil and B-cell populations was unexpected. Cacalano et al. offer several possible explanations for this result, but strong evidence to support any one is lacking.