Introduction

The humoral immune response, also known as antibody-mediated immunity, is one of the two branches of the adaptive immune response. It involves the production of antibodies, also known as immunoglobulins (Ig), by B cells in response to an antigen. The purpose of the humoral immune response is to neutralize and remove antigens from the body.

B cell activation and differentiation in humoral immune response

• B cells are activated by the binding of an antigen to the B cell receptor (BCR) and the simultaneous interaction with T helper cells (CD4+).
• Activated B cells differentiate into two main types: plasma cells and memory B cells.
• Plasma cells secrete high-affinity antibodies against the specific antigen, while memory B cells remain in circulation to provide long-term protection against the same antigen.

Antibodies in humoral immune response

• Antibodies, also known as immunoglobulins (Igs), are Y-shaped proteins that are specific to a particular antigen.
• They are composed of four polypeptide chains: two heavy chains and two light chains.
• There are five classes of antibodies: IgA, IgD, IgE, IgG, and IgM, each with unique properties and functions.

Mechanisms of Action

• Antibodies can neutralize antigens in a number of ways, such as by forming immune complexes, opsonization, and complement activation.
• Immune complexes are formed when antibodies bind to antigens, making them more visible to phagocytic cells.
• Opsonization is the process by which antibodies make antigens more visible to phagocytic cells by coating them.
• Complement activation is the process by which antibodies trigger the activation of the complement system, leading to the lysis of cells or the formation of a membrane attack complex.

Limitations

• The is not effective against certain types of antigens, such as intracellular pathogens, and can have a delayed onset compared to the cell-mediated immune response.
• The production of antibodies can also result in the formation of harmful immune complexes, leading to conditions such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Conclusion

The humoral immune response, also known as antibody-mediated immunity, is one of the two branches of the adaptive immune response.

It involves the production of antibodies by B cells in response to an antigen.

Antibodies, also known as immunoglobulins (Igs) can neutralize antigens in a number of ways such as forming immune complexes, opsonization and complement activation.

The humoral immune response has some limitations and it is not effective against certain types of antigens and can have a delayed onset.