Introduction to Antibodies

These flashcards cover key concepts about antibodies, their structure, functions, classes, and roles in the immune response.

What is the primary function of antibodies?

Antibodies help protect from infection by neutralizing infectivity, enhancing phagocytosis, mediating ADCC, activating immune cells, and facilitating complement-mediated lysis of pathogens.

What are the two main types of chains that make up immunoglobulins?

Immunoglobulins are made up of light chains (L) and heavy chains (H), with each antibody consisting of 2 identical light chains and 2 heavy chains.

How many immunoglobulin classes do humans have?

Humans have 5 classes of antibodies: IgM, IgD, IgG, IgA, and IgE.

What distinguishes affinity from avidity in antibody-antigen interactions?

Affinity refers to the strength of the interaction between a single antigen-binding site and its antigen, while avidity measures the total binding strength across all antigen-binding sites.

What role does maternal IgG play in newborns?

Maternal IgG is transferred to the newborn and provides passive immunity against infections.

What is class switching in relation to B cells?

Class switching is a process where activated B cells change the type of antibody they produce, transitioning from IgM or IgD to other isotypes such as IgG, IgE, or IgA.

What are the secretory forms of IgA, and where are they primarily found?

Secretory IgA consists of two IgA units joined by a J chain and is primarily found at mucosal surfaces, such as in milk, tears, and saliva.

What triggers B cell activation according to the Clonal Selection Theory?

B cell activation is triggered when antigens bind to their specific B cell surface antibody molecules.

How does the presence of antibodies assist in the immune response?

Antibodies prevent pathogens from attaching to host cells, enhance the efficiency of phagocytosis, and activate the complement system.

What is an important characteristic of IgE and its medical significance?

IgE is produced in very small quantities but plays a critical role in host defense against parasitic infections and is responsible for allergic reactions.