Comparative analysis of influenza A(H3N2) virus hemagglutinin specific IgG subclass and IgA responses in children and adults after influenza vaccination

Abstract

Two different influenza vaccines are generally used in many countries; trivalent live attenuated influenza vaccine (LAIV3) and trivalent inactivated influenza vaccine (IIV3). Studies comparing the antibody response to IIV3 and LAIV3 commonly investigate the seroprotective response by hemagglutination-inhibition (HI) assay. However, there is limited data regarding comparative analysis of IgG subclass and IgA responses induced by LAIV3 and IIV3. Fifteen children <5years received 2 doses of LAIV3 while 14 children aged 10-17years received one dose. In addition, 15 adults were vaccinated with either intranasal LAIV3 or intramuscular IIV3. We analyzed the H3N2 humoral responses by HI assay and the hemagglutinin (HA) specific IgG1, IgG2, IgG3, IgG4 and IgA1 responses by ELISA. Furthermore, we investigated the avidity of induced IgG antibodies. Pre-existing seroprotective HI antibodies were present in adults (73%) previously vaccinated with IIV3. Vaccination resulted in a significant increase in HI titers in all groups, except LAIV3 vaccinated adults. Furthermore, a negative correlation between age and HI titers in LAIV3 vaccinated subjects was observed post-vaccination. LAIV3 in children and IIV3 in adults induced HA-specific IgG1, low IgG3 but no IgG2 or IgG4. Moreover, significant IgA1 responses were only induced in children. Interestingly, IIV3 and LAIV3 induced IgG antibodies with comparable and significantly augmented avidity post-vaccination in children and adults. Our results suggest that age and/or exposure history play a significant role in determining the antibody response. Clinical trial registry: ClinicalTrials.gov NCT01003288 and NCT01866540.

Analysis of Anti-Influenza Virus Neuraminidase Antibodies in Children, Adults, and the Elderly by ELISA and Enzyme Inhibition: Evidence for Original Antigenic Sin

“…S1D to F) distribution of anti-N1, anti-N2, and anti-influenza B virus NA antibodies. In general, the pattern reflected the distribution seen with antibodies to HA (30–32), with the exception of elevated IgG4 titers against NC99 N1 and elevated IgG2 titers against Yam88 NB (Fig. S1).…”

How to assess the effectiveness of nasal influenza vaccines? Role and measurement of sIgA in mucosal secretions

“…Concerning influenza‐specific IgA detection, the procedure needs to be adapted due to the absence of a standardized human influenza‐specific IgA reference. The ELISA procedure in principle has been described elsewhere . In brief, ELISA plates are coated with an influenza antigen (preferably purified HA) and a capture antibody (anti‐human IgA).…”

“…One approach may be to use the “limit of blank” according to the following formula: “ Average of background signals (OD Blank ) plus 2 standard deviations.” In this case, the cutoff value will be calculated without the need for a specific human sample; only ELISA reagents will be added to the coated plate together with the influenza antigen, and the background signal will be used to calculate the cutoff. An alternative possibility is the calculation of the cutoff value as the reciprocal of the highest dilution that shows an absorbance value >0.2 of the OD value after subtraction of the background as previously described …”

“…An important feature of the ELISA assay is that it can measure different classes of IgG, IgM, and IgA present both in serum and in mucosal samples. [71][72][73] Currently, there are two main methods ( Figure 2) of detecting influenza-specific sIgA responses in nasal wash/swab and saliva samples. 74,75 The two methods differ mainly in terms of the strategy adopted for the standardization of the samples to be analyzed, which…”

“…The ELISA procedure in principle has been described elsewhere. 73 important to run multiple samples collected from the same subject at different time points in the same ELISA plate.14 According to this method, the value of influenza-specific IgA normalized through the total IgA content will be expressed as "(Influenza-Specific IgA (U/mL)/ Total IgA (µg/mL)) * 100. ".…”