Leukocytes vs Lymphocytes
Both leukocytes and lymphocytes are described as components of blood. Blood is a special type of connecting tissue composed of a fluid matrix called plasma and several kinds of cells and other formed elements that circulate within the plasma. Blood has many functions, including transportation, regulation, and protection. There are three types of formed elements of blood cells and cell fragments, namely, erythrocytes, leukocytes, and platelets. Each element of the blood has a specific task in the process of maintaining the body’s health and homeostasis. All the cells and other elements develop from pluripotent stem cells.
Leukocytes are also referred to as white blood cells. They represent less than 1% of the cells in the human blood. These leukocytes are larger than the erythrocytes and contain nuclei inside the cell body. Leukocytes are found not only in the blood plasma, but also in interstitial (tissue) fluid as they can migrate out of blood capillaries through the intercellular spaces into the fluid. Depending on the staining properties of granules in the leukocyte plasma, they can be divided into two categories, namely, granular leukocytes and nongranular leukocytes.
Granular leukocytes include neutrophils, eosinophils, and basophils which have granules in their cytoplasm. Nongranular leukocytes are monocytes and lymphocytes, which do not contain the granules in their cytoplasm. Each type of leukocyte has a specific function in defending against invading microorganisms and other foreign substances. Among these cells, neutrophils are the most numerous, followed in order by lymphocytes, monocytes, eosinophils, and basophils.
In humans, lymphocytes arise from lymphoid stem cells. Lymphocytes are mainly responsible for carrying out adaptive immunity responses in the humans. These cells have receptor proteins on their surfaces that can recognize specific antigens and direct immune response against them. There are two types of lymphocytes, namely, B lymphocyte cells and T lymphocyte cells.
B cells respond to the antigens by secreting antibodies or immunoglobulin and are responsible for humoral immunity. T-cells are responsible for cell-mediated immunity. They do not produce antibodies. Instead, immune responses are regulated by directly attacking and destroying the specific antigens. The cytoplasm of the lymphocyte usually does not contain large granules. The cells can be easily identified by their large nucleus surrounded by a small amount of cytoplasm.
What is the difference between Leukocytes and Lymphocytes?
• Lymphocytes are a type of leukocyte.
• All the leukocyte cell types except lymphocyte arise from a stem cell line called myeloid stem cells. Lymphocyte cells arise from a stem cell line called lymphoid progenitor cells.
• Lymphocytes are responsible for adaptive immunity whereas the other leukocytes except lymphocytes are responsible for innate immunity in humans.
• Unlike leukocytes, lymphocytes can be further divided into B lymphocytes and T lymphocytes. These B cells and T cells are responsible for humoral and cell-mediated immunity.
• There are five types of leukocytes; one of them is lymphocyte.