In Reply.—Dr Khan and his associates call attention to one aspect of neutrophil function, ie, chemotaxis, that we agree may be an important factor in host defense both for the mother in preventing breast abscesses and for the infant in providing neutrophils for antigen processing. Unfortunately, we have already imposed on the Journal by submitting an unusually lengthy article and so omitted details of this particular assay. We chose to focus on data more specific to Salmonella infection.
Methods for chemotaxis under agarose were identical to those previously published1 except that we quantitate the migrating cells with a micrometer disk (scale, 5 mm/100 units, type 9) eyepiece grid. After counting cells on the chemotactic side and control side of the neutrophil well, the chemotactic index is calculated using the following formula: chemotactic index (CI) = No. of cells on the chemotactic side/No. of cells on the control side. Our