c-fos and c-jun mRNA expression in activated cord and adult lymphocytes: An analysis by northern hybridization

Background and Objectives: To further analyze the neonatal immune response to an antigenic challenge such as blood transfusion, c-fos and c-jun mRNA expression were analyzed in twelve in-vitro-stimulated normal cord blood and ten in-vitro-stimulated normal adult peripheral blood lymphocyte samples. Materials and Methods: Lymphocyte samples were stimulated by either the mitogen phytohemagglutinin (PHA) or the monoclonal antibody alpha CD3. Proliferation rate and Northern blot hybridization were employed. Results: Cord lymphocytes revealed a greater proliferation rate with PHA and alpha CD3 than adult lymphocytes (p = 0.0081 and 0.0023, respectively). In addition, Northern blot analysis of cord and adult samples revealed similar maximal increases in c-fos (99 +/- 15 and 126 +/- 11%, p = 0.0126) and c-jun (123 +/- 9 and 185 +/- 38%, p = 0.0291) mRNA expression, respectively, as early as 15 min post-alpha CD3 stimulation. Adult lymphocytes showed an equivalent increase in mRNA expression of c-fos and c-jun (140 +/- 25 and 155 +/- 31%) at 30 min post-PHA stimulation, while cord lymphocyte maximum c-fos and c-jun expression (82 +/- 6 and 142 +/- 12%) occurred at 15 min post-PHA stimulation (c-fos, p = 0.0354; c-jun, p = 0.0112). Conclusion: Although cord lymphocyte proliferation rates were significantly greater than those of adult lymphocytes following stimulation, lymphocyte activation, as analyzed by c-fos and c-jun mRNA expression, appears similar in both cord and adult samples. We conclude that cord lymphocyte activation exhibits an adult-type profile.