Human lymphocyte proliferation. I. Correlation between activated and proliferating T-lymphocytes

Area of Science:

• Immunology
• Cell Biology

Background:

• Human peripheral blood lymphocytes are crucial for immune responses.
• Lymphocyte activation by mitogens like Concanavalin A (Con A) and phytohemagglutinin (PHA) is a key indicator of immune function.
• Understanding lymphocyte cell cycle progression is vital for interpreting immune responses.

Purpose of the Study:

• To analyze the response of human peripheral blood lymphocytes to Con A and PHA.
• To correlate cell cycle phase distribution with lymphocyte proliferation markers.
• To investigate the impact of different culture media on lymphocyte response.

Main Methods:

• Quantification of lymphocyte cell cycle phases (G0 and G1) using cytofluorometry.
• [3H]thymidine incorporation assay to measure lymphocyte proliferation.
• Comparison of lymphocyte responses in media supplemented with autologous plasma, AB-serum, and a defined serum-free medium (RPMI 1640).

Main Results:

• A high correlation was observed between the number of Con A or PHA-induced G1 cells and [3H]thymidine incorporation in healthy donors when using autologous plasma or AB-serum.
• The defined serum-free medium revealed distinct medium requirements for PHA-stimulated lymphocytes, dividing donors into two groups.
• Immunoregulatory mechanisms in T-lymphocytes occur during the G1 phase.

Conclusions:

• Cytofluorometric analysis of lymphocyte cell cycle phases, particularly the G1 phase, strongly correlates with proliferation assays.
• The study highlights donor-dependent variations in lymphocyte response to mitogens, influenced by culture medium composition.
• Cell cycle analysis offers a valuable tool for interpreting altered lymphocyte responses to lectins and antigens, potentially improving diagnostic capabilities in immunology.