Extracellular pathogens are most effectively targeted by humoral immunity and the production of antibodies, while intracellular pathogens cannot be reached by antibodies and must therefore be targeted by the cellular immune response. Direction of this response to a particular pathogen is largely governed by the ratio of T-cell types produced and the cytokines these cells secrete locally. More subtle control of this response may also be achieved. For example, TH2 cells directly stimulate B cells to class switch, producing immunoglobulin isotype , which is useful in targeting _.

For example, TH2 cells directly stimulate B cells to class switch, producing immunoglobulin isotype IgE, which is useful in targeting parasitic worms.

Explanation:

Immunoglobulin E, or IgE, is a protein present in low blood concentrations that is usually found on the surface of some blood cells, especially basophils and mast cells, for example.

Because it is present on the surface of basophils and mast cells, which are cells that normally appear in higher blood concentrations during allergic reactions, IgE is usually related to allergies; however, its concentration may also be increased in blood due to diseases caused by parasites. and chronic diseases, such as asthma, for example. This is because TH2 cells directly stimulate B cells for class switching, producing the IgE isotype of immunoglobulin, which is useful in targeting parasitic worms.