Bacterial vaccines & their evaluation

Composed and Presented By

TEAN ZAHEER

2013-ag-2605

DVM, FVS, UAF.

Bacterial Vaccines

 Injection of a weakened/ killed microbe in order to stimulate the immune system against the microbe, thereby preventing disease.

Vaccinations, or immunizations, work by stimulating the immune system.

Bacterial diseases can be prevented by the use of immunizations.

Active immunity is induced by vaccines prepared from bacteria or their products.

How Bacterial Vaccines Work?

Types of bacterial vaccines

A-Capsular polysaccharide vaccines

B-Toxoid vaccines

C-Purified protein vaccines or ppd

D-Live attenuated bacterial vaccines

E-Killed bacterial vaccines

A CAPSULAR POLYSACCHARIDE VACCINES

These are a type of subunit vaccines which are prepared by the use of capsular polysaccharides of bacteria.

Examples:(1) Streptococcus pneumoniae vaccine contains

the capsular polysaccharides of the 23 most prevalent types.

(2) Neisseria meningitidis vaccine contains capsular polysaccharide of four important types (A, C, W-135 and y).

(3) Other examples: Salmonella typhi & Haemopilus influenza.

B. Toxoid Vaccines :

Toxoids are actually inactivated toxins Inactivation may be done by the use of

formalin, heat, BPL. EXAMPLES

(1)Corynebacterium diphtheriae vaccine contains the toxoid (formaldehyde-treated exotoxin).

(2)Other examples Clostridium tetani, Bordetella pertusis

C. PURIFIED PROTEIN VACCINES :

These are the vaccines that are composed of some purified protein component of bacteria

Examples: The vaccine against Lyme disease contains a

purified outer surface protein (OspA) of Borrelia burgdorferi as the immunogen.

Bacillus anthracis vaccine contains "protective antigen" purified from the organism.

Other Examples:Bordetella pertussis

D. LIVE. ATTENUATED BACTERIAL VACCINES:

These vaccines are produced by weakening a live bacterial cell in such a way that it loses pathogenicity but retains immunogenicity.

Example: Mycobacterium bovis, Salmonella typhi

E. KILLED BACTERIAL VACCINES:

The microorganism is killed in such a way that it retains its immunogenicity

Examples:

Vibrio cholera, Yersinia pestis, Coxiella

burnetii

EVALUATION OF BACTERIAL VACCINES

Evaluation of bacterial vaccines may involve the followings:

1. Safety Test:

Determines that the vaccine is safe to use for the purpose it is developed.

It may involve initial testing in lab animals and later on in humans volunteers.

Allergic reactions can be recorded.

EVALUATION OF BACTERIAL VACCINES

2. Sterility Test:

Determines that vaccines contain only the vaccine agent or other intentionally added immunogenic constituents.

No contaminant( E.g other bacteria, fungi, etc.) should be the part of vaccine.

It is done by culturing the preparations on different culture media to identify contaminants.

EVALUATION OF BACTERIAL VACCINES

3. Potency Test

Determines the effectiveness of vaccines so that detectable and protectable Ab titers may be achieved.

It is performed by injecting different dose of vaccines to lab animals and then identifying a potent dose.