Introduction to Lab Ex. 22: Immunology I - Bacterial Agglutination - Immunoprecipitation.

Introduction to Lab Ex. 22: Immunology I

- Bacterial Agglutination

- Immunoprecipitation

Introduction to Lab Ex. 22: Immunology I – Bacterial Agglutination- Immunoprecipitation

Immune responses include all the activities of the immune systemtoward maintaining the healthy status of the host.

These would include protecting against pathogens – foreign antigens

Specific Immune responses are one of two kinds: Antibody-mediated Cell-mediated

Antibodies are proteins secreted by specific immune cells to counteract and rid the antigens (and thus the pathogens they may be associated with)

Antibodies are specific for the antigen that trigger their formation.Depending on the nature of the antigen the antigen-antibody reactions

result in different reactions, ex. Agglutination or precipitation

Table 1. Serological classification of some common Salmonella species.

Salmonella species Serological groupS. typhimurium B S. paratyphi C C1 S. enteriditis D S. anatum E

agglutination no agglutination?

Antibody specificity known (S. enteriditis)Salmonella species identity not known (?)Agglutinationreaction between antibody and particulate antigen

 BACTERIAL AGGLUTINATION. is the reaction between a particulate antigen and its specific antibodies

Bacterial agglutination

?

Bacterial agglutination

?

agglutination no agglutination

S. aureus S. epidermidis

agglutination no agglutination?

Antibody specificity known (S. aureus)- antigen on the surface of bacteria Staphylococcus species identity not known (?)

Bacterial agglutination

Bacterial agglutination

S. aureus S. epidermidis

?

agglutination no agglutination

S. aureus S. epidermidis

Latex beads(dyed blue)

S. aureus-specificantibodies

Bacterial agglutination

S. aureus S. epidermidis

?

agglutination no agglutination

Note: these latex beads are dyed red

S. aureus S. epidermidis

Bacterial agglutination (new procedure).

#1Mark your bacterial agglutination cards

S. aureus S. epidermidis

Bacterial agglutination

#2Mix the latex agglutination reagent dropper bottle and dispense one drop onto each circle

Bacterial agglutination

#3Using a sterile toothpick , pick up and smear 1 suspect colony from your negative control in the proper ring.

#4Using a NEW sterile toothpick , pick up and smear 1 suspect colony from your positive control in the proper ring.

#5Using a NEW sterile toothpick , pick up and smear 1 suspect colony from your unknown in the proper ring.

S. aureus S. epidermidis

S. aureus S. epidermidis

Bacterial agglutination (Part B).

#6Pick up and gently rock the card for 20 seconds and observe for agglutination under normal lighting conditions

?Bacterial antigen: Agglutination with anti-S. aureus :

S. aureus

S. epidermidis

unknown

Immunoprecipitation- is the reaction between a soluble antigen and its specific antibodies-soluble antigens are smaller and in solution; complexing with antibodies make these

bigger and they fall out of solution as a precipitate –visible to the eye.

Antibody specificity known (toxin, protein, etc.)Antigen presence or identity not known (?)Precipitationreaction between antibody and soluble antigen

Immunoprecipitation

Antibody specificity known (toxin, protein, etc.)Antigen presence or identity not known (?)Precipitationreaction between antibody and soluble antigen

Immunoprecipitation

Immunoprecipitation

Reaction of nonidentity

Reaction ofidentity