What does the CD45 marker generally identify?

The CD45 marker is primarily known as a common leukocyte antigen and is broadly expressed on all hematopoietic cells, which include leukocytes such as lymphocytes, monocytes, dendritic cells, and granulocytes. As a pan-leukocyte marker, CD45 serves as a crucial identifier for leukocytes, enabling their differentiation from non-hematopoietic cells.

In the context of immunology and flow cytometry, the presence of CD45 is utilized to confirm the cell lineage of various populations of white blood cells and to analyze immune cell dynamics. By understanding the role of CD45, researchers and clinicians can distinguish between different cell types in the immune system, which is essential for diagnostic and therapeutic purposes.

While other options suggest specific subsets of leukocytes, such as natural killer cells, youth lymphocytes, and T cells, they do not encompass the broad representation of all leukocytes that the CD45 marker signifies. Thus, identifying CD45 as a marker for leukocytes provides a comprehensive framework for understanding immune cell populations.