Failure to distinguish ultrastructurally between T4+ (helper) and T8+ (suppressor/cytotoxic) T-cell subsets

Human peripheral T-cell subpopulations revealed by monoclonal antibodies by means of a rosetting method were isolated by micromanipulation and submitted to electron microscopic analysis. The T3+ subset (total T cells) displayed a high degree of heterogeneity, including multiple transitional forms, from cells with a high nuclear to cytoplasmic ratio and rare organelles to cells with a low nuclear to cytoplasmic ratio and a complex system of cytoplasmic organelles. T4+ (inducer/helper) and T8+ (suppressor/cytotoxic) cell subpopulations were shown to have no evident distinguishing characteristics. They both displayed the same morphological variation mentioned for T3+ lymphocytes. On morphometric analysis, these two cell subsets were very similar, with only slight differences for cell surface roughness, volume of mitochondria, extent of nuclear indentation, and surface area of the rough endoplasmic reticulum. The significance of these minor morphological differences is discussed.