Question

The identification of the different types of anti-VSG antibody in hosts infected by Trypanosome would be helpful to determine how long the host has been infected for.

a) True, because based on the number of antigen-specific antibodies (IgM and IgG) produced we can establish exactly how many months the parasite had been in the host circulatory system
b) False, because the parasite is coated only by one type of VSG at the time and therefore when antibodies against the new VSG are produced, the other antibodies specific for the previous VSG antigens disappear
c) False, we could detect antibodies against previous antigens in lower titer and antibodies against the current antigen in higher titer but we would not be able to predict exactly for how long the host has had the infection
d) False, because we can just detect IgG

Answer 1

The correct statement is option (c), indicating that while antibodies against previous and current VSG antigens can be detected, they cannot precisely determine the duration of the host's infection due to antigenic variation and the persistence of antibodies.

Step-by-step explanation:

Identification of the different types of anti-VSG antibody would not be helpful to determine precisely how long the host has been infected by the Trypanosome. The false statement that best represents the reality is option (c): False, we could detect antibodies against previous antigens in lower titer and antibodies against the current antigen in higher titer, but we would not be able to predict exactly for how long the host has had the infection. This is because Trypanosoma brucei, the causative agent of African sleeping sickness, is known to employ antigenic variation to change its surface glycoproteins, eluding the immune system's attempts to clear the infection. Antibodies against former variants of VSG antigens might exist at lower levels, while those against the currently expressed VSG could be at higher levels, but this information does not provide a precise timeline of infection. Additionally, antibodies may persist in the blood for months to years after initial exposure, which can indicate past exposure rather than active infection.