Immunization booster injections

Artificially acquired immunity against some diseases may require periodic booster injections to keep an adequate antibody level (or antibody titer) circulating in the blood. A booster injection is the administration of an additional dose of die vaccine to boost the production of antibodies to a level diat will maintain die desired immunity. The booster is given months or years after die initial vaccine and may be needed because die life of some antibodies is short. 

Immunization procedures and schedules vary depending on the laboratory. Usually an initial series of injections is followed by booster injections some weeks later. Animals are generally bled 7-14 days after each booster injection and the characteristics of the serum determined. Serum may be collected or pooled following numerous booster injections and(or) the animal may be exsanguinated. 

Two goats were immunized three times during the first 2 weeks with 1 mg of the antigen emulsified in 1 ml of Freund s complete adjuvant at several subcutaneous sites near regional lymph centers. Booster injections of 3 mg of antigen were administered at monthly intervals. The animals were bled 7 days after each boost. After several months of immunization, the titer and affinity of the antibody response was judged sufficient for use. 

Antiserum Production The immunogen, carboxymethylmorphine-bovine-serum-albumin, is emulsified with equal volume of complete Freund s adjuvant. Initial immunization doses are injected into the New Zealand albino rabbits and later on this followed up with booster injections after a period of 6 weeks. The antiserum titer is determined with each booster dose injection and is duly harvested when the titre value is maximum. This is diluted suitably and employed in the radioimmunoassay. ... 

Immunization and Antibody Production The immunogen 3-hemisuccinyloxyflurazepam, is emulsified with complete Freund s adjuvant. It is injected intradermally into two female New Zealand albino (white) rabbits. Repeated doses are administered twice at interval of two weeks. Subsequently, booster injections of the thick-immunogen-emulsion-paste are administered after a span of 6-weeks. The antibody is harvested when its titer level is high enough, diluted to the suitable-level and employed in the RIA. 

The preparation of any MAB commences with the generation of lymphocytes sensitized to the antigen of choice. Conventionally this is done by the immunization of a mouse against the antigen followed by repeated booster injections until a suitable serum response has been obtained. Optimal results are obtained if the immune... 

Where antigens are introduced into the body intravenously, they usually travel rapidly to the spleen, followed by the fast production of an antibody. Subcutaneous or lntradermal injection of antigens most frequently localizes in the lymph nodes and antigens that are inhaled favor local sensidzadon. In some cases, such as tetanus immunization, loxin produced by the bacteria may be slow and insufficient to provoke a significant immunologic reaction. Thus, the requirement for properly timed booster injections. 

Serial measurements of antibody response after primary immunization or a secondary booster injection. 

A wide range of doses and immunization schedules has been used successfully. A convenient schedule for immunization of rabbits is to inject 200-500 fjLg of conjugated protein, emulsified in complete Freund s adjuvant, intradermally and subcutaneously on the first day, and to inject the same dose in incomplete adjuvant on days 14 and 21. Serum can be obtained 5-7 days later. Further bleedings may be done weekly, with intra-dermal booster injections given if the serum antibody levels fall. After an... 

Animals immunized with Freund s emulsions should be bled 7-10 days after booster injections. If the blood is taken from a vein rather than by cardiac puncture, two or three bleeds can be taken on successive days, but the animal should then be rested for 3-4 weeks before further bleeding or before boosting again if the original antiserum was not of satisfactory quality. After intravenous injection antibody levels rise and then fall more rapidly and bleeds should be collected 5-7 days after the last dose. It is often helpful to fast the animals overnight to minimize lipemia, but do not deprive them of drinking water. 

Freund s adjuvant. At monthly intervals, the rabbits were boosted intramuscularly with 1 mg of enzyme, again emulsified in complete Freund s adjuvant. Immune sera were collected 1 week after each booster injection. The antiserum used in the immunochemical application described here was collected 1 week after the sixth boost. 

Hepatitis B vaccine (inactivated B virus surface antigen adsorbed on aluminium hydroxide adjuvant) provides active immunity against hepatitis B infection, and in coimtries of low endemicity it is given to individuals at high risk, including healthcare professionals. Immunity is conferred for at least 5 years and can be supplemented by booster injections. 

Clostridial neurotoxins are very toxic. However they are ineffective in individuals immunized with the corresponding toxoids. In most countries children are vaccinated with tetanus toxoid and this is sufficient to provide full protection against tetanus for decades. A booster injection of tetanus toxoid (available from health authorities) before starting research with TeTx is advisable. On the other hand, the vaccine for BoNT/A, B, C, D and E is not commercially available, but can be obtained from the Center for Disease Control (CDC, Atlanta, GA). Due to the rather low efficacy of the BoNTs vaccine, a protective serum anti-BoNT titre is generally, but not always, achieved. Human anti-TeTx antibodies and horse anti-BoNT antibodies are also available from health authorities, and their injection immediately after accidental penetration of the toxin into the circulatory system is sufficient to prevent the disease. 

PAM are weakly or moderately immunogenic, while PSS and PVP are more potent Ag comparable to some natural Ag. Typically, the more immunogenic PSS exhibits a dose-response relationship (Table 111). Doses as low as 10 pg can induce detectable Ab by the RIA, but almost a million-fold increase in the immunizing dose of PSS is required in order to obtain a substantially higher Ab titre, and the optimal response decreases rather rapidly (Table III). An apparent secondary response is observed when the mice were immunized with a sub-optimal dose followed by a booster injection (Table IV). This secondary response decreased to a lower level of Ab titre in about 1 week. Similarly, PVP is also known to induce such responses in mice ( ). 

The immunization consists of three subcutaneous injections given 2 weeks apart tbllow-ed by three additional subcutaneous injections given at 6, 12. and 18 months. Annual booster injections of die vaccine are recommended thereafter. 

Collect immune serum 7—10 d after each booster injection and isolate the serum as described under step 2. Store the serum in aliquots at-80 C. Repeat this procedure until no fiirther increase in serum titer occurs (see Note 5). 

Most vaccines require two or three primary immunizations, followed by a booster for optimum immune response. If one injection of the immunization schedule is missed, it leads to manifold loss of effective antibody titers. According to WHO statistics, more than 30% of the patients do not return for the next injection at each period of the immunization schedule. The effect of noncompliance is most severe in third world countries, where more than a million children die each year from vaccine-preventable diseases. 

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