Age-Dependent Features of Evolving Humoral Immunity in Children

Andreev

Смердова

et al. 2020

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Despite adherence to the policy of mass measles vaccination in the majority of countries, this infection still remains far from being fully eradicated. Measles outbreaks are reported worldwide, when the vast majority of cases are recorded in subjects of 18—35 years of age. Studies on assessing measles IgG antibody level in different regions of Russia reveal increased percentage of measles seronegative subjects among young adults. Current study was aimed at investigating formation of humoral and cellular immunity after measles vaccination in seronegative adults aged 18 to 30 years old. There were enrolled 50 measles seronegative healthy volunteers aged 18 to 30 years old. Level of anti-measles IgM and IgG antibodies was measured by ELISA (Vector-Best, Russia). Subclasses of measles specific IgG antibodies were analyzed by ELISA, by replacing IgG conjugate for IgG1, IgG2, IgG3, IgG4 conjugates, whereas measles specific IgA antibodies were estimated by ELISA with IgA conjugate (Polygnost, Russia) at a concentration of 1 μg/ml. Antibody avidity was assessed by ELISA (Euroimmun, Germany). Cell-mediated measles immunity was estimated by CD107a surface expression on CD8hi T cell subset stimulated by measles virus-derived antigens. A specific cellular response to measles antigens before vaccination was detected in 50% of examined subjects, whereas 40% samples showed no signs of cellular immune response, with 10% of remaining cases described as equivocal. It was found that 6 weeks after vaccination all vaccinated subjects developed measles specific IgG antibodies at protective level reaching 1.33 (0.85—1.82) IU/ml [Me (LQ—UQ)]. Anti-measles IgA antibodies were of 0.655 (0.423—1.208) IU/ml [Me (LQ—UQ)]. However, no measles specific IgM antibodies were detected 6 weeks after vaccination. In addition, primary type of immune response (dominant low-avidity anti-measles antibodies IgG3 subclass) to measles vaccination was observed in 24 out of 50 subjects, whereas 26 subjects developed secondary type of immune response (high-avidity anti-measles antibodies dominated by IgG1 subclass). A measles specific cellular immune response was observed in 47 of the 50 examined subjects, and in 3 volunteers it was equivocal. Further analysis revealed a cohort of subjects who were not vaccinated against measles (18 subjects), although 60% of them provided medical record on previous dual measles vaccination occurred in childhood. Another cohort consisted of subjects who had medical record of measles vaccination in childhood (32 subjects), but lost protective measles antibodies produced by plasma cells (23 subjects), and memory T cells (3 subjects), or measles antibodies and memory B cells (6 subjects) over time. Such pattern evidences that measles-specific cellular and humoral arms immune responses were developed and maintained independently of each other.

Section: материалы и методыunclassified

Formation of humoral and cellular immunity to measles vaccine in adults

Andreev

Смердова

et al. 2020

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Comparison of the Primary and Secondary Humoral Immune Response to Vaccination by “Priorix”

Алешкин

2014

Резюме. С целью проследить и сопоставить особенности формирования, поддержания и функционирования иммунологической памяти, 20 здоровых детей, согласно российскому календарю прививок, были привиты вакциной Приорикс (корь, краснуха, паротит), а через 5 лет ревакцинированы той же вакциной. В сыворотке крови методом ИФА определяли специфические IgM, IgA и IgG антитела к кори, краснухе и паротиту, их авидность, а также субклассы специфических IgG. Показано, что специфический иммунный ответ на вакцину Приорикс формируется с участием антител трех классов: IgM, IgG и IgA. Антитела классов G и A сохраняются и на этапе иммунологической памяти, обнаруживая бустер-эффект при ревакцинации, особенно у лиц с низким уровнем антител. Первоначально низкая авидность антител постепенно повышается и достигает 60-70% для вирусов кори и краснухи и остается низкой у антител к эпидемическому паротиту. При ревакцинации авидность антител к кори, краснухе и эпидемическому паротиту не меняется. При первичном иммунном ответе основным является IgG3, также участвуют IgG1 и IgG4. На этапе поддержания иммунологической памяти и ответа на ревакцинацию превалирует IgG1, а IgG3-и IgG4-антитела становятся минорными.

Common Mechanisms of Specific Humoral Immune Response’ Shaping and Sustaining by the Example of Immune Response to Measles and Rubella Viruses

2014

Abstract. T follicular helper cells (Tfh) are a CD4+ Th cell subset promoted the cognate control of antigen-specific B cell immunity. Upon first contact with antigen-primed B cells, Tfh can support either extrafollicularly differentiation into short-lived plasma cells (PC) or enter follicles to form germinal centers (GC). Signaling lymphocytic activation molecule (SLAM) interaction between Tfh and activated B-cells is essential for GC development. Within GC, Tfh regulates the fate of antigen-specific GC B cells expressing high-affinity B cell receptors to develop memory B cell (Bm) or long-lived PC. Short-lived PC produce low-affinity IgM and IgG3 early antibodies. Both Bm and long-lived PC have high-affinity class-switched IgA and IgG, predominantly IgG1 antibodies. Measles virus uses human SLAM-molecule as a cellular receptor. SLAM is expressed on dendritic cells and activated B and T-cells. This is an important regulator of the isotype switching and antibody affinity maturation, especially IgG3-IgG1 switching. Development of long-term humoral immunity, charac terized by the formation of high-affinity predominantly IgG1 antibodies, is a critical component of protective immunity to pathogens and the major goal of vaccination. However, the mechanisms involved in the shaping and sustaining of long-term humoral immunity remain poorly understood.