What is the second most common type of white blood cell that boosts immune defense?

The second most common type of white blood cell that boosts immune defense is lymphocytes. These cells play a crucial role in the immune system by identifying and responding to pathogens, such as viruses and bacteria. Lymphocytes can be further categorized into B cells and T cells, which are involved in antibody production and orchestrating the immune response, respectively.

Monocytes, while important for immune function, primarily differentiate into macrophages and dendritic cells to help engulf pathogens and present antigens. Neutrophils are actually the most abundant type of white blood cells and are key players in the initial response to infection. Eosinophils are primarily involved in combating parasitic infections and in mediating allergic reactions, making them less central to general immune defense compared to lymphocytes. Thus, the prominence and role of lymphocytes in enhancing immune defense contextually establish them as the second most common white blood cell type.