Host Response to Protozoa: Insights into Immune Defenses and Pathogen Virulence

host response to protozoa

extracellular parasites: humoral responseintracellular parasites: cell-mediated response

Protozoa are single-celled microscopic organisms that can cause a wide range of infections in humans and animals. The host response to protozoa can vary depending on the type of protozoan and the immune status of the host.

The initial response of the host to protozoa is the activation of innate immune cells such as neutrophils, macrophages, and natural killer cells. These cells are responsible for phagocytosis and destruction of the protozoa and the release of cytokines that activate adaptive immunity.

Adaptive immune response against protozoa requires the activation of T and B cells. These immune cells recognize the protozoa antigens and produce specific antibodies that can neutralize and eliminate protozoa. T cells are also necessary for the direct destruction of infected cells, providing the key defense mechanism against some protozoa infections such as Leishmania.

The host response to protozoa can also be enhanced by the participation of other immune cells such as dendritic cells, which present protozoa antigens to T cells; and eosinophils, which are important in the control of helminth infections but can also contribute to the elimination of some protozoan parasites such as Entamoeba histolytica.

The effectiveness of the host response to protozoa depends on the balance between the protozoan virulence factors and the host immune defenses. Protozoans employ different mechanisms such as antigenic variation, immune evasion, and suppression of host immune responses to evade host defenses and establish chronic infections.

In summary, the host response to protozoa involves the activation of different immune cells and the production of specific antibodies. The immune response can be enhanced by the participation of other immune cells such as dendritic cells and eosinophils. However, protozoans have evolved different mechanisms to evade host immune defenses and establish chronic infections.

More Answers: