Relationships between 2H4 (CD45RA) and UCHL1 (CD45RO) expression by normal blood CD4+CD8−, CD4−CD8+, CD4−CD8dim+, CD3+ CD4−CD8− and CD3−CD4−CD8− lymphocytes

Abstract

We characterized and established relationships between the expression of membrane 2H4 (CD45R A) and UCHL1 (CD45RO) by enriched lymphocyte fractions prepared by selective immunomagnetic depletion of monoclonal antibody‐defined populations. Cell fractions analysed in this study could be divided into two broad groups according to the presence (CD.3⁺VCD4⁺CD8⁻, CD3⁺CD4⁻CD8⁺ CD3⁺ CD4⁻ CD8^dim+ and CD3⁺CD4⁻ CD8⁻) or absence (CD3⁻CD4⁻CD8^dim+ and CD3⁻ CD4⁻ CD8⁻) of the CD3 antigen. Preliminary studies confirmed a reciprocal relationship for CD45RA and CD45RO expression by major lymphoid components and further showed that the level or intensity of membrane 2H4 staining (2H4⁺, 2H4^int and 2H4⁻) could be directly related to UCHLI expression. As a reflection of their differential functions, the various CD3⁺ populations examined showed much greater heterogeneity in 2H4 and UCHLI expression. CD3⁺CD4⁺CD8 cells generally showed significant proportions of 2H4⁺, 2H4^int and 2H4⁻ components, whereas the CD3⁺CD4⁻CD8⁺ population was characterized by a predominance of 2H4⁺ cells. The results of this current investigation further suggested a higher proportion of dual‐positive (2H4⁺ UCHL1⁺) cells and a much greater degree of inter‐individual variation than previously suspected. In contrast to CD3* lymphocytes, natural killer (NK) associated CD3⁻CD4⁻ CD8^dim+ and CD3⁻CD4⁻CD8⁻populations were mostly 2H4⁺ with only minor 2H4^int components and very low expression of UCHL1. An additional observation of note was that the proportions of 2H4⁺ and 2H4⁻ cells comprising the CD4⁺ CD8⁻ fraction in any given individual was highly correlated (P= 0·002) with the distributions of 2H4⁺ and 2H4⁻ components within the CD4⁻ CD8⁺ fraction. This suggests the possible existence of a common control mechanism for the acquisition of immunological memory by distinct lymphocyte populations and further indicates that individual variations in the distribution of 2H4/UCHLI lymphocyte subpopulations may be a direct consequence of immunological experience’ rather than age alone.