Antibody quantity versus quality after influenza vaccination

Abstract

The correlates for protection against influenza infection are incompletely characterized. We have applied an ELISA strategy that distinguishes antibodies against native viral surface antigens (potentially neutralizing) from antibodies directed against internal and denatured viral proteins (not neutralizing) to three groups of vaccinated subjects: (1) participants in a study of repeated annual vaccination, (2) elderly subjects and (3) patients with Systemic Lupus Erythematosus compared to control subjects. Antibody increase after vaccination was inversely related to the level of pre-existing antibodies in all groups; most subjects had significant initial antibody levels and showed little increase in amount of antibody after vaccination, but the avidity of their serum antibodies tended to increase. Antibodies against denatured virus proteins varied with vaccine formulation; vaccines that are more recent have less total protein for the same amount of native hemagglutinin. We propose an index consisting of rank order of antibody level plus antibody avidity, both measured against native virus, plus hemagglutination-inhibition antibody titer, as a useful measure of immunity against influenza.

Figure 1. Binding patterns seen among vaccinated subjects

These results are native ELISAs for four control subjects in the lupus study. The vaccine used contained A/California/7/2004 as the H3N2 component. For an older virus, we used A/Beijing/353/89 because all the subjects were born before 1989. Top panel: antibodies against California/04. Lower panel: antibodies against Beijing/89. Subject A shows moderate increase of anti-Calif/04 antibodies after vaccination, with no increase against “old” virus Beijing/89. Subject B shows moderate levels of pre-existing antibodies against California/04 but they are of low affinity. Good response to vaccination in both amount and avidity. Some increase in affinity of antibodies against Beijing/89 after vaccination. Subject C shows high level of pre-existing antibodies. No increase after vaccination Subject D shows high levels of non-specific antibodies. No increase after vaccination

Figure 2. Fold increase in Amax is inversely related to pre-vaccination levels of antibodies

Panel A plots fold increase in Amax against pre-vaccination Amax for the three studies. Panel B is the same plot for fold increase in Ka. It shows that subjects with higher pre-vaccination levels of antibody may show an increase in avidity after vaccination, even though there is no increase in antibody amount.

Figure 3. Protein and NA content of vaccines and purified viruses

Panels A, B and C show the total protein, HA titer and NA activity (fluorescence units) of a dose in five years of vaccines. The results in panel B reflect varying sizes and avidities of HA rosettes in the vaccine, since each vaccine contains 15 µg of each of the three HAs (total 45 µg). Panels D and E show HA titer and NA activity of some of the viruses that were contained in the vaccines used in A–C. Results were calculated per 45 µg of HA for comparison with A–C.