On a second encounter with a pathogen, a patient should have a higher titer of IgG.
1. IgG is the most abundant type of antibody in the blood and tissues.
2. During a secondary encounter with a pathogen, the immune system has memory cells (specifically memory B cells) that "remember" the pathogen from the initial exposure.
3. Memory B cells can rapidly produce large quantities of IgG antibodies upon re-exposure to the same pathogen.
4. IgG antibodies are effective at neutralizing pathogens, enhancing phagocytosis (engulfing of pathogens by immune cells), and activating the complement system for pathogen destruction.
5. Therefore, during a second encounter with a pathogen, the patient would have a higher titer of IgG compared to the first encounter, aiding in a faster and more effective immune response to the pathogen.
In summary, IgG is the antibody that shows an increased titer upon a second encounter with a pathogen due to the presence of memory B cells that mount a quicker and stronger immune response.
