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After seroconversion, sufficient concentration of the specific antibody exists in the blood, and the serological assay will detect the antibody. The individual is now seropositive for the antibody. [14] During seroconversion, when the amounts of antibody and antigen are very similar, it may not be possible to detect free antigen or free ...
The plaque reduction neutralization test is used to quantify the titer of neutralizing antibody for a virus. [1] [2] The serum sample or solution of antibody to be tested is diluted and mixed with a viral suspension. This is incubated to allow the antibody to react with the virus. This is poured over a confluent monolayer of host cells.
The presence of detectable levels of a specific marker within the serum is considered seropositivity, while the absence of such levels is considered seronegativity. HIV/AIDS [ edit ]
A viral titer is the lowest concentration of a virus that still infects cells. To determine the titer, several dilutions are prepared, such as 10 −1, 10 −2, 10 −3, ... 10 −8. [1] The titer of a fat is the temperature, in degrees Celsius, at which it solidifies. [4] The higher the titer, the harder the fat.
Clinically, measured IgG antibody levels are generally considered to be indicative of an individual's immune status to particular pathogens. A common example of this practice are titers drawn to demonstrate serologic immunity to measles, mumps, and rubella (MMR), hepatitis B virus , and varicella (chickenpox), among others.
It has a very good efficacy of about 95%, [6] with protection lasting for more than 30 years, even after the anti-HbsAg antigen titers have fallen. [7] The RTS,S also makes use of HBsAg. It is a mixture of a version of malaria surface antigen grafted to HBsAg (RTS) and ordinary HBsAg (S), both made through recombinant DNA.
Changes in viral load are usually reported as a log change (in powers of 10). For example, a three log increase in viral load (3 log10) is an increase of 10 3 or 1,000 times the previously reported level, while a drop from 500,000 to 500 copies would be a three-log-drop (also 3 log10). [citation needed]
Seroconversion is defined as an increase in HI (Hemagglutination-Inhibition) antibody titer of at least 4-fold, with a minimum post-vaccination HI titer of 1:40. I believe this refers to results from a Viral Hemagglutination Assay