Difference in antibody reactivity between complement fixation and immune adherence hemagglutination tests with virus...

Area of Science:

• Virology
• Immunology
• Serology

Background:

• Complement fixation (CF) and immune adherence hemagglutination (IAHA) are serological assays used to detect viral antibodies.
• Antibody affinity and subclass can influence the performance of different diagnostic assays.

Purpose of the Study:

• To compare the reactivity of early and late antibodies in IAHA and CF assays for rotavirus and Japanese encephalitis virus.
• To evaluate the utility of IAHA and CF assays in diagnosing recent viral infections and serotyping viruses.

Main Methods:

• Detection of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies using CF and IAHA assays.
• Experimental infection of guinea pigs with Japanese encephalitis virus.
• Analysis of antibody titers in patient and animal sera.

Main Results:

• Infantile gastroenteritis virus (rotavirus) IgM antibodies showed no IAHA reactivity.
• Early IgG antibodies to Japanese encephalitis virus (a flavivirus) exhibited weak IAHA reactivity compared to CF.
• Late IgG antibodies demonstrated higher titers in IAHA than in CF, suggesting increased affinity.

Conclusions:

• Low-affinity antibodies are less efficient in IAHA reactions.
• A low IAHA/CF antibody titer ratio may indicate a recent rotavirus infection.
• IAHA offers higher type specificity than CF for serotyping antigenically cross-reacting viruses.