What does a positive result for CD2 antigen indicate in lymphocytes?

A positive result for the CD2 antigen in lymphocytes indicates the presence of T cells. CD2 is a surface protein that plays a critical role in T cell communication and activation. It is primarily expressed on T lymphocytes and is notably involved in their interaction with other cells during immune responses.

When CD2 is detected on lymphocytes, it confirms the existence of T cells, as B cells, NK cells, and monocytes do not typically express this marker. B cells, for instance, are characterized by surface markers like CD19 and CD20, whereas NK cells are identified by markers such as CD56 and CD16. Monocytes, on the other hand, are generally identified by markers including CD14 and CD68.

Thus, the presence of CD2 is a specific indicator of T cell lineage, making this option the accurate choice when interpreting the results of immunophenotyping in lymphocytes.