Living organisms have developed mechanisms of resisting infections or pathogens by the action of antibodies or sensitized leukocytes. This system can either be natural or acquired and it offers defense against invaders such as bacteria, viruses and parasites that have the potential to cause sicknesses. The acquired immunity is further classified as either humoral or cellular immunity and they differ and resemble as discussed below.
To begin with, humoral immunity is an adaptive system brought about by B cells which are the main cells that secrete antibodies in form of soluble proteins which circulate in blood. Other cell types involved here are the T cells and the macrophages. This is an extracellular activity acting on extracellular microbes and their toxins involved are B cell receptors (BCR) whose receptor surfaces are mainly CD40, CD21 and Fc. Here, the antigens are identified by the humoral antibody secreted by plasma B cells (Kim et al., 2017). This type of immunity has a rapid response and it does not act on transplants and tumor cells.
Delegate your assignment to our experts and they will do the rest.
In contrast, cellular immunity is a cell mediated adaptive system brought about by T cells. The main cells involved are the helper T cells, natural killer cells and the cytotoxic cells. Whereas humoral immunity is an extracellular activity, cellular immune system is intracellular acting on intracellular microbes such as bacteria, viruses, parasites and tumor cells (Kirimanjeswara et al., 2008). The receptors involved are T Cell Receptors (TCR) whose accessory surface molecules includes CD2, CD3, CD4, CD8 and CD28. Here, the antibodies are secreted by the T cells and their response is a bit delayed with respect to humoral immune. The advantage of cellular immunity is that it can act on tumor cells and transplants unlike in the former.
Nevertheless, humoral and cellular immunity share some things in common. For instance, they are adaptive immunity acquired from the environment. The immune response produced in both targets a particular pathogen (Kirimanjeswara et al., 2008). They are also controlled from the phagocytes.
In conclusion, humoral and cellular immunity are adaptive targeting a particular pathogen. In humoral type, the antibodies act directly on the pathogens but in cellular type the antibodies cause necrobiosis in which the affected cells are killed. Therefore, humoral immunity destroys extracellular pathogens while cellular type destroys intracellular pathogens.
References
Kim, H. R., Choi, J. Y., Kim, K. S., Jung, Y. S., Cho, J. Y., Hwang, D. Y., & Song, H. K. (2017). Comparison of humoral and cell-mediated immunity in three different C57BL/6N mouse substrains. Laboratory animal research , 33 (2), 132-139.
Kirimanjeswara, G. S., Olmos, S., Bakshi, C. S., & Metzger, D. W. (2008). Humoral and cell ‐ mediated immunity to the intracellular pathogen Francisella tularensis. Immunological reviews , 225 (1), 244-255.
