What Is a Cell-Mediated Immunity?

Specific immunity (also known as adaptive immunity or adaptive immunity), this type of immunity only targets one pathogen. It is the body's ability to resist infection through acquired infections (healed or asymptomatic infections) or artificial vaccination (bacteria, vaccines, toxoids, immunoglobulins, etc.). It is usually formed after the stimulation of antigenic substances such as microorganisms (immunoglobulin, immune lymphocytes), and can specifically react with the antigen.

Specific immunity

Specific immunity

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1. Naturally immune. One got something

Standardized specific immunotherapy

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Specific immunity can be obtained through illness, recessive infection, vaccination, injection of antitoxins, and so on.

Specific immune immunization method

Active immunity

Natural active immunity: sickness, recessive infection.

Artificial active immunization; vaccination, toxoid, etc.

Passive immunity

Natural passive immunity: through placenta, colostrum.

Artificial passive immunity; injection of antitoxin, gamma globulin, cytokines, etc.

Artificial immunity is the use of artificial methods to inoculate vaccines, toxoids, etc. or contain certain specific antibodies, cellular immune preparations, etc. to inoculate the human body to enhance the body's disease resistance.

Biological products are used for artificial immunogens (bacteria, toxoids, etc.), immune serum, cellular immune preparations and diagnostic preparations (tubulin, diagnostic serum, diagnostic antigen, etc.), and are collectively referred to as biological products.

Specific immune artificial active immunity

It is a method of artificial inoculation to input antigenic substances (bacteria, vaccines, toxoids) into the body to stimulate the body to actively generate specific immunity. It is mainly used for the specific prevention of diseases.

(A) vaccine

1. Dead vaccines are harvested from cultured and proliferated highly immunogenic bacteria, and are made by physical and chemical methods such as pertussis, typhoid, Japanese encephalitis and other vaccines.

2. Live vaccines are also called attenuated vaccines. Live attenuated or non-virulent live pathogens discovered from nature or screened by artificial cultivation. Such as BCG, influenza, polio and other live vaccines. Live vaccines are inoculated and immunized through natural infection routes The effect is good, but it has potential dangers: recovery of virulence (although rarely found); causing complications in other parts, such as postpox encephalitis; activation of latent virus; causing persistent infection, etc.

3. The new live vaccine uses genetic engineering technology to control the mutation of the virus and prepare a vaccine that can proliferate in the body and induce an antiviral immune response.

Both live and dead vaccines have advantages and disadvantages

The live vaccine is inoculated through natural infection routes, and the immune effect is good, which produces humoral immunity and cellular immunity.

Advantages: Proliferate without causing disease, small dosage and few times;

Generate local and systemic immunity with good immune effect;

It has expanded immune effect and lasting immunity.

Disadvantages: Easy to inactivate, transport and storage inconvenient; Possibility of retoxication;

Immunodeficiency and immunosuppression are prohibited;

Inactivated vaccines are administered intramuscularly and usually only trigger a humoral immune response.

Advantages: easy to save and transport; no danger of retoxication; simple production method;

Disadvantages: local immunity cannot be generated; multiple vaccination is required, the dose is large; local and systemic reactions are obvious;

4. The genetically engineered vaccine obtains the target gene with the protective epitope of the pathogen, and introduces it into the prokaryotic or eukaryotic expression system to obtain the protective antigen of the pathogen, such as the hepatitis B genetically engineered vaccine. It is safe and efficient. Economical, mass production, etc.

5.Recombinant vector vaccine A vaccine made by transferring a gene encoding a protein antigen into an attenuated virus or bacteria.

6. Synthetic vaccines are peptides synthesized based on the amino acid sequence of pathogen antigens, but there are still some problems that require further research.

7. Subunit vaccine: refers to a vaccine made by artificially lysing the virus and extracting the infection-related subunit components on the capsid or envelope. The advantage is the removal of viral nucleic acids (which may transform cells) and other components (which may cause fever) Etc. side effects).

8. DNA vaccine is also called gene vaccine or nucleic acid vaccine. Recombinant gene fragments and plasmids encoding pathogen immunogens that can cause protective immune response are recombined. The recombinant is directly injected into the host body, so that the antigen is continuously expressed in the body, and protective body fluids are induced. A new vaccine for immunity and cellular immunity. This nucleic acid is both a carrier and an antigen that can be expressed in eukaryotic cells, stimulating the body to produce a specific and effective immune response. Its advantages: good immune effect, can stimulate the body's comprehensive immune response, immunity Long-lasting, simple preparation, low cost, convenient storage and transportation, can not only combine immunity, but also have the dual functions of prevention and immunotherapy. The disadvantage is that the safety needs further research and confirmation.

9. Transgenic plant vaccine The gene encoding a certain pathogen protective antigen is transferred into a plant and expressed in plants. While eating these plant foods, a vaccination is completed.

10. Therapeutic vaccine Emerging vaccines for the purpose of treating diseases, such as Staphylococcus's own vaccine.

(B) Toxoid Bacteria Exotoxin after 0.3% -0.4% formaldehyde treatment, the toxicity disappears and still maintains its immunogenicity, namely toxoid. Such as tetanus, diphtheria toxoid, etc.

Specific immune artificial passive immunity

Refers to injecting the body with immune antibodies or other cellular immune preparations containing specific antibodies, so that the body immediately obtains specific immunity. It is mainly used for treatment or emergency prevention. Comparison of two artificial immune systems

1. Antitoxin Toxoids are injected into horses several times. After the horse produces high titer antitoxins, blood is collected, the serum is separated, and purified. It is commonly used in clinical anti-toxins such as tetanus, diphtheria, gas gangrene, and botulinum. Care should be taken to prevent the occurrence of type I hypersensitivity.

2.Antibacterial serum is only used for the treatment of diseases caused by multi-resistant strains.

3. Placenta gamma globulin is generally used for prevention.

4. Other immune preparations currently being tested are transfer factor (TF), immune ribonucleic acid (iRNA), thymosin, interferon (IFN), interleukin-2 (IL-2), cytotoxic T cells (CTL) and LAK cells, etc.