UPTAKE OF RADIOACTIVE CALCIUM (⁴⁵Ca) BY NEUTROPHILS (PMN) FROM HUMAN NEONATES

Abstract

Abnormal chemotaxis, deformability, and lectin capping of neonatal PMN may be due to abnormal plasma membrane structure or function (eg, altered Ca uptake after pertubation). We studied ⁴⁵Ca uptake by blood PMN from 45 neonates. PMN and ⁴⁵Ca were incubated at 37°C. Basal ⁴⁵Ca uptake plateaued after 15 min and resting samples were taken. PMN were then stimulated; ⁴⁵Ca uptake increased for 15 min, and samples were taken. Samples were centrifuged through silicone oil with > 99.9% PMN and <0.5% free ⁴⁵Ca entering the pellet. Pellet radioactivity = PMN ⁴⁵Ca uptake. ⁴⁵Ca uptake (mean cpm) by resting PMN (N=45) was 1163 neonates and 1685 controls (P <.0001). ⁴⁵Ca uptake increased (2.2 - 145 fold) comparably (P > .05) in neonatal and control PMN after soluble stimuli (NaF and DMSO) or zymosan particles. Stimulated values (mean cpm) for neonates and controls were: NaF 113115 & 107421 (N=8); DMSO 164215 & 157944 (N=10); zymosan 2932 & 4380 (N=10). Neonatal PMN responded superiorly (P < .02) to FMLP; values were 4157 neonates vs 1297 controls. In conclusion, basal ⁴⁵Ca uptake by resting neonatal PMN was significantly decreased. The importance of this finding is undefined. Neonatal PMN increased ⁴⁵Ca uptake as well as or better than control PMN in response to several stimuli. Thus, abnormal membrane-dependent functions cannot be explained by failure of neonatal PMN to acquire extracellular calcium following stimulation.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD