The specificity of the PCR depends crucially upon the primers. The following factors are important in choosing effective primers

Primers should be 17 to 30 nucleotides in length

A GC content of about 50% is ideal. For primers with a low GC content, it is desirable to choose a long primer to avoid a low melting

 temperature.

Sequences with long runs (i.e., more than three or four) of a single nucleotide should be avoided.

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Use of Passive vaccine, 

a. Immune deficiency

b, Toxin or venom exposure with immediate threat to life

c, Exposure to pathogens that can cause death faster

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#Unit 4. Cell Communication and Cell Signaling

Passive vaccine- Measles, Rabies, Snake bite, Hepatitis A and B, Cytomegalovirus, Diphtheria

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#Unit 4. Cell Communication and Cell Signaling

Active Immunization

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For good vaccine

a. The vaccine must be safe

b. It must be effective in preventing infection

c. Activation of the humoral and cell-mediated

d. Development of long-term immunologic memory

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Clinical trials

Phase I clinical trials assess human safety; a small number of volunteers are monitored closely for adverse side effects.

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Phase II where effectiveness against the pathogen in question is evaluated.