Immunizing Agents PDF

IMMUNIZING AGENTS A N C E R L A Charles Andre Villaceran, RMT L V I IMMUNITY - body's ability to prevent the invasion of pathogens or resist harmful microorganisms TYPES OF IMMUNITY INNATE – General barriers, Physical Barrier, Biological barrier A...

IMMUNIZING AGENTS A N C E R L A Charles Andre Villaceran, RMT L V I IMMUNITY - body's ability to prevent the invasion of pathogens or resist harmful microorganisms TYPES OF IMMUNITY INNATE – General barriers, Physical Barrier, Biological barrier ADAPTIVE A N C E R L L A V I  A N C E R L L A V I  A N C E R L L A V I TYPES OF IMMUNITY A N C E R L L A V I  Active – stimulate the body’s immune system -> antibodies or cell mediated immunity, or both, which protects against infectious agent E.g. Vaccines or Toxoids A N C E Passive – consists of providing temporary R L L A administration of exogenously produced protection through the antibody I V for first 3-6 months of life E.g. Transplacental: protective Immunoglobulin injection: for specific purposes  A N C E R L L A V I  A N C E R L L A V I  NATURAL IMMUNITY (two types) Natural Passive A N – type of natural immunity in the form of Antibodies from a C E - last for a short period of time only R mother to her fetus across the placenta or through her milk. L L A Natural Active V I - person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response - Bacteria, virus, toxins - B-cells and T-cells will attack the Antigen ARTIFICIAL IMMUNITY (two types) -immune response that develops Antibody from exposure to a specific antigen Artificial passive A N C E R - immunity comes from injected antibodies created within a different person or an animal. These antibody-containing preparations are termed antiserum. L A - Immunoglobulins/ Antisera and Anti-toxins L Artificial active V I - Antigen is presented and Antibodies will fight and remain alert for future infection - Vaccine IMMUNIZING AGENTS Immunizing agents are biological preparations that stimulate the A N immune system to develop immunity against diseases. E R substances or organisms that provoke an immune C L L A response (produce immunity) when introduced into the body V I Purpose: Prevent infectious diseases, reduce morbidity and mortality, and contribute to herd immunity.  TYPES OF IMMUNIZATION 1. Active Immunization - The body produces its own immune response. A N - Long-term immunity. C E R L A Examples: Vaccines (Live attenuated, inactivated, subunit, toxoid, mRNA). L 2. Passive Immunization V I - Preformed antibodies are transferred to the individual. - Short-term protection. Examples: Maternal antibodies, immunoglobulin therapy. DIFFERENT KINDS OF IMMUNIZING AGENTS VACCINES – suspension of attenuated live or killed microorganisms A N administered to induce immunity and thereby prevent infectious disease. E R IMMUNOGLOBULINS – contains 15% to 18% protein obtained by cold C L L A ethanol fractionation of large pools of blood plasma. V I Primarily indicated for certain immunodeficient persons, passive immunization against measles and Hep A, and special IV preparations for immunoglobulin deficient patiens ANTISERA – blood serum containing monoclonal or polyclonal antibodies that is used to spread passive immunity to many diseases VACCINES -Antigen administration to stimulate production of specific Antibodies to protect individual against particular disease. A N C E R L L A V I TYPES OF VACCINES 1. Live Attenuated Vaccines (LAVs) Contains weakened pathogens that mimic natural infection. A N C Advantages: Strong, long-lasting immunity.E R Examples: Measles, Mumps, Rubella (MMR), BCG, Oral Polio (OPV), Varicella. L A Disadvantages: Not suitable for immunocompromised individuals. L 2. Inactivated (Killed) Vaccines V I Contain killed pathogens. Examples: Inactivated Polio Vaccine (IPV), Hepatitis A. Advantages: Safer, no risk of reversion. Disadvantages: Requires booster doses. TYPES OF VACCINES 3. Subunit, Recombinant, and Conjugate Vaccines Use antigenic parts of the pathogen. Examples: Hepatitis B, HPV, Pneumococcal, Meningococcal. Advantages: Fewer side effects. Disadvantages: May require boosters. A N 4. Toxoid Vaccines C E R Contain inactivated bacterial toxins. Examples: Tetanus, Diphtheria. L L A Advantages: Strong immune response. Disadvantages: Requires multiple doses. V I 5. mRNA & Viral Vector-Based Vaccines Use genetic material to instruct cells to produce antigens. Examples: Pfizer & Moderna (mRNA), AstraZeneca & J&J (Viral Vector). Advantages: Fast development, high efficacy. Disadvantages: Cold storage requirements, new technology.  MECHANISM OF ACTION Step 1: Vaccine introduces antigen to the body. A N Step 2: Antigen-presenting cells (APCs) process and present antigens to T-helper cells. C E R L L A Step 3: T-helper cells activate B cells. V I Step 4: B cells differentiate into plasma cells, producing antibodies. Step 5: Memory B and T cells are formed for long-term immunity.  “HERD IMMUNITY” - When a large percentage of the population is vaccinated, it provides indirect protection to unvaccinated individuals. A N Herd Immunity Thresholds: C E R Measles: ~95% L L A COVID-19: ~60-70% I V groups (e.g., infants, Clinical Significance: Protects vulnerable immunocompromised individuals). Vaccine Schedules and Boosters Primary Series: Initial doses to build immunity. Booster Doses: Reinforce immunity over time. Examples: >Tetanus booster every 10 years. A N E R >Hepatitis B: Recommended for high-risk individuals after initial series. C >MMR (Measles, Mumps, Rubella): Additional dose recommended for international travelers or during outbreaks. L L A V I >Varicella (Chickenpox): Booster dose recommended for healthcare workers and high-risk adults. >HPV (Human Papillomavirus): Booster doses recommended depending on age of initial vaccination. >COVID-19: Booster doses recommended periodically based on emerging variants and immunity duration. >Pneumococcal (PCV13 & PPSV23): Booster doses for elderly and immunocompromised individuals. >Influenza: Annual booster due to virus mutation.  FACTORS CONTRIBUTING TO DIFFERENT RESPONSES OF PEOPLE TO VACCINES 1. Immune System Differences A N 1.1 Some individuals have stronger immune responses, producing long-lasting antibodies after just one or two doses. Others may need additional booster shots to maintain protective immunity. responds to a vaccine. C E R 1.2 Factors like age, genetics, and underlying health conditions affect how well a person’s immune system 2. Pre-existing Immunity L L A V I 2.1 People who have had prior exposure to the disease (through infection or vaccination) may already have some level of immunity, reducing the need for frequent boosters. 3. Vaccine Type and Effectiveness 3.1 Some vaccines provide long-term immunity with just one or two doses, while others require multiple boosters to sustain protection over time. 3.2 Certain vaccines, like mRNA COVID-19 vaccines, may require periodic boosters due to waning immunity and new virus variants.  FACTORS CONTRIBUTING TO DIFFERENT RESPONSES OF PEOPLE TO VACCINES 4. Lifestyle and Environmental Factors A N 4.1 People with frequent exposure to infectious diseases (e.g., protection. C E R healthcare workers) may need more boosters to ensure ongoing L L A 4.2 Nutrition, stress, and other external factors can also influence immune response. V I 5. Individual Variation in Antibody Production 5.1 Some individuals naturally produce more or longer-lasting antibodies, while others may see a quicker decline in their antibody levels, requiring additional boosters.  Passive Immunization & Immunoglobulin Therapy Sources: 1. Maternal antibodies (placenta, breast milk). A N E R 2. Monoclonal & polyclonal antibody treatments. C Examples: L L A V I >Rabies immunoglobulin (post-exposure prophylaxis). >Hepatitis B immunoglobulin (HBIG). Uses: Emergency protection, immunodeficient patients. Vaccine Safety and Adverse Effects Common mild reactions: Fever, swelling, redness. Severe reactions (rare): A N 1. Anaphylaxis - severe allergic reaction that happens quickly and needs immediate medical treatment. C E R L L A 2. Guillain-Barré Syndrome (GBS) - rare condition where the immune system attacks the nerves, causing weakness or paralysis, but most people recover. Contraindications: V I 1. Severe allergic reactions to vaccine components. 2. Pregnancy (for live vaccines). 3. Immunocompromised conditions.  A N C E R L L A V I ANTISERA AND ANTITOXINS Specific immunoglobulins prepared from the plasma of immunized animals or humans. Cheap but less effective. Lasts only for a short period of time Examples. Snake venom, anti-tetanus, rabies vaccine A N C E R L L A V I IMMUNOGLOBULINS A N C E R L L A V I  A N C E R L L A V I  READING, AND INTERPRETATION OF LFIA TESTING KITS WITH IgG and IgM LINES Recall the basics: A N LFIA kits are based on the principle of immunochromatography. When a sample (serum, or plasma) is added to the sample well, it migrates along the nitrocellulose membrane via capillary action. C E R DO NOT FORGET!!! L L A V I TEST LINES FOR THIS TYPE OF KITS ARE PRE-COATED WITH ANTIBODIES THAT CAPTURE IgG and IgM, forming visible lines if they do. IgM Line: Captures IgM antibodies (early response to infection) IgG Line: Captures IgG antibodies (later response, indicating immunity or past infection) Control Line (C): Ensures that the test is valid by detecting the movement of reagents along the strip.  INTERPRETATIONS Case 1: Negative Result Control Line (C): Visible A N IgM Line: Absent IgG Line: Absent C E R L L A I Reading: No detectable IgG or IgM antibodies. Interpretation: (could be) 1. The individual is not infected. V 2. The infection is in the very early stage (before antibody production). 3. The individual has not been exposed to the specific antigen.  INTERPRETATIONS Case 2: Positive for IgM Only A N Control Line (C): Visible IgM Line: Visible C E R IgG Line: Absent L L A Interpretation: V I *Take note: IgM is the first antibody produced during an immune response* This result suggests: 1. A recent or current infection (acute phase). 2. The individual is in the early stage of exposure.  INTERPRETATIONS Case 3: Positive for IgG Only A N Control Line (C): Visible IgM Line: Absent C E R IgG Line: Visible L L A Interpretation: V I *Take note: IgG indicates long-term immunity or a past infection* This result suggests: 1. The individual had a previous infection or has been vaccinated (if applicable). 2. No active infection is present.  INTERPRETATIONS Case 4: Positive for Both IgM and IgG A N Control Line (C): Visible IgM Line: Visible C E R IgG Line: Visible L L A Interpretation: The presence of both IgM and IgG indicates: V I A current or recent infection, with IgM reflecting an ongoing immune response and IgG indicating an advanced stage of the immune response.  INTERPRETATIONS Case 5: Invalid Test A N Control Line (C): Absent IgM Line: Absent or Visible C E R IgG Line: Absent or Visible L L A Interpretation: The test is invalid (can be) due to: V I 1. Insufficient sample volume. 2. Improper procedure or defective kit. ALWAYS REMEMBER: The control line must always appear for the test to be valid. PRACTICAL CONSIDERATIONS USING IgG/IgM Testing Kits A N A. Timing of Sample Collection: C E R The production of IgM and IgG antibodies depends on the stage of infection: L L A IgM appears within 5–7 days after infection and declines after a few weeks. I IgG appears later (7–14 days) and persists for months to years. V B. LFIA results must be correlated with clinical symptoms and other laboratory findings. C. Ensure the kit is specific to the antigen being tested to avoid false positives from similar antigens. D. Understand the limitations of the kit as per the manufacturer’s validation. Always consider the Sensitivity and Specificity of the testing kit Summary Table for Interpretation Result IgM Line IgG Line Control Line Interpretation No infection or very Negative Absent Absent A N Visible early stage of C E R infection. Recent or current IgM Positive Visible L L A Absent Visible infection (acute phase). IgG Positive Absent V I Visible Visible Past infection or immunity. Current or recent IgM + IgG Positive Visible Visible Visible infection (active immunity). Test invalid; repeat Invalid Any Any Absent using a new kit. EXAMPLE OF QUALITATIVE PLUS QUANTITATIVE TESTING COMBINED (INTERPRETATION) A N C E R L L A V I  A N C E R L L A V I  CONSTITUENTS OF IMMUNIZING AGENTS Suspending fluid A N - This frequently is as simple as sterile water of saline E R - It may be a complex fluid containing small amounts of protein or C L L A other constituents derived from the medium or biologic system in V I which the immunizing agent is produced (serum proteins, egg antigens, cell culture – derived antigens)  Preservatives, stabilizers, antibiotics These components of vaccines are used N - To inhibit or prevent bacterial growth in viral culture or the final A product - To stabilize the antigen C E R L L A !!!Alergic reactions mayV I occur if the recipient is sensitive to any of these additives!!!  Adjuvants - enhances the immune response to vaccines containing inactivated microorganisms. - can be in a form of aluminum salt, or oil-in-water adjuvants  A N C E R L L A V I