Antigen O dan Antigen H - Definisi dan Perbedaan
Perbedaan antara Antigen O dan Antigen H
- Struktur permukaan bakteri memiliki heterogenitas antigen yang cukup besar. Seringkali antigen ini digunakan sebagai bagian dari sistem klasifikasi serologis untuk bakteri.
- Klasifikasi dari 2000 atau lebih Salmonella yang berbeda terutama didasarkan pada jenis antigen O (rantai samping LPS) dan H (flagel).
- Jenis antigenik bakteri dapat menjadi penanda virulensi, terkait dengan sifat klonal patogen, meskipun mungkin sebenarnya bukan faktor virulensi.
Perbedaan utama antara antigen O dan antigen H meliputi:
S.N. |
Character |
O Antigen |
H Antigen |
1. |
Referred to as |
Somatic Antigen or Boivin antigen |
Flagellar antigen |
2. |
Determination |
Based on oligosaccharides associated with
lipopolysaccharide. |
Based on flagellar proteins. |
3. |
Cell wall |
Part of the cell wall lipopolysaccharide (LPS). |
Not a part of the cell wall. |
4. |
Composition |
Polysaccharide. |
Proteinaceous (Flagellin). |
5. |
Heat sensitivity |
Somatic antigens are heat stable. |
Flagellar antigens are heat-labile. |
6. |
Alcohol sensitivity |
Resistance to alcohol |
Sensitive to alcohol |
7. |
Formaldehyde sensitivity |
Formaldehyde labile |
Formaldehyde stable |
8. |
Extraction |
Trichloro-acetic acid is used for extraction of O
antigens. Since the property was first shown by Boivin, O
antigen alternatively referred to as boivin antigen. |
Formaldehyde is used for extraction of H antigens. |
9. |
Immunogenicity |
Less immunogenic |
Highly immunogenic |
10. |
Antibody levels |
Produces antibody formation with low titres. |
Induces antibody formation with high titres. |
11. |
Antibody formation |
Rapid and Early |
Rapid and Sustained |
12. |
Lifespan |
Antibody levels fall off quickly. |
Persists for longer periods. |
13. |
Antibody indicates |
O antibody appears early, disappears early:
indicates recent infection. |
H antibody appears late, disappears late: lndicates
convalescent stage. |
14. |
Type of agglutination reaction shown |
Produces compact, chalky and granular clumps. |
Produces cottony, fluffy precipitates. |
15. |
Reaction time |
Agglutination takes place slowly |
Agglutination takes place rapidly. |
16. |
Optimum temperature for reaction |
Optimum temperature for agglutination is 55’°C. |
Optimum temperature for agglutination is 37’°C. |
17. |
Reaction observed with |
Round bottom Felix tube are used to see
agglutination. |
Conical bottom Dreyer’s tube is used to see
agglutination. |
18. |
Role as virulence factor |
The most important virulence factor responsible for
endotoxic activity; it protects the bacteria from phagocytosis and
bactericidal effect of complement. |
Makes the bacteria motile, hence contributing to
their virulence. |
19. |
Existence in phases |
No phases |
Flagellar antigens exist in two alternative phases-
Phase I and II. Most o f them are biphasic except S. Typhi
which is monophasic. |
20. |
Widal test |
In Widal test, O antigen of Salmonella Typhi
is used. |
In WidaI test, H antigens of S.Typhi, S.Paratyphi
A and B are used. |
21. |
Use in classification |
Serogrouping of salmonellae is based on the O
antigen. |
Serogroups are differentiated into serotypes based
on H antigen. |
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