Primary vs Secondary Response

Feature

Primary Immune Response

Secondary Immune Response

Time of response

Slower (appears after 4–7 days)

Faster (appears within 1–3 days)

Antibody concentration

Lower peak antibody levels

Much higher peak antibody levels

Type of antibodies produced

Mainly IgM at first, followed by IgG

Mainly IgG, also IgA or IgE depending on antigen

Affinity of antibodies

Lower affinity (less specific binding)

Higher affinity due to affinity maturation

Duration of response

Short-lived

Long-lasting

Memory cells

Naïve B cells are activated; memory cells formed

Memory B cells are quickly reactivated