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Cross-subtype immunity against avian influenza in persons recently vaccinated for influenza.

Gioia C, Castilletti C, Tempestilli M, Piacentini P, Bordi L, Chiappini R, Agrati C, Squarcione S, Ippolito G, Puro V, Capobianchi MR, Poccia F - Emerging Infect. Dis. (2008)

Bottom Line: Avian influenza virus (H5N1) can be transmitted to humans, resulting in a severe or fatal disease.No correlation between influenza-specific CD4 T cells and humoral responses was observed.N1 may possibly be a target for both cellular and humoral cross-type immunity, but additional experiments are needed to clarify this point.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Virology, National Institute for Infectious Diseases Lazzaro Spallanzani, Istituti di Ricovero e Cura a Carattere Scientifico, Via Portuense 292, Rome, Italy.

ABSTRACT
Avian influenza virus (H5N1) can be transmitted to humans, resulting in a severe or fatal disease. The aim of this study was to evaluate the immune cross-reactivity between human and avian influenza (H5N1) strains in healthy donors vaccinated for seasonal influenza A (H1N1)/(H3N2). A small frequency of CD4 T cells specific for subtype H5N1 was detected in several persons at baseline, and seasonal vaccine administration enhanced the frequency of such reactive CD4 T cells. We also observed that seasonal vaccination is able to raise neutralizing immunity against influenza (H5N1) in a large number of donors. No correlation between influenza-specific CD4 T cells and humoral responses was observed. N1 may possibly be a target for both cellular and humoral cross-type immunity, but additional experiments are needed to clarify this point. These findings highlight the possibility of boosting cross-type cellular and humoral immunity against highly pathogenic avian influenza A virus subtype H5N1 by seasonal influenza vaccination.

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Related in: MedlinePlus

Humoral response against vaccine preparation and influenza virus (H5N1) before (t0) and after (t1) seasonal influenza vaccination. Hemagglutination inhibition (HI) test was used to calculate the antibody (Ab) titer against vaccine preparation (top panel), whereas a neutralization test was used to calculate the antibody titer against influenza (H5N1) (bottom panel) in healthy donors enrolled in the study at baseline (t0) and 1 month after seasonal influenza vaccination (t1). At baseline (white bars), all donors had a detectable level of human influenza antibodies. At t1 (black bars), 28 donors (73.6%) (indicated by *) showed a >4 fold increase of Ab titer against vaccine preparation (HI) over t0. After seasonal influenza vaccination, 13 serum samples (33.3%) (indicated by *) from the study population showed a 20-fold increase of neutralizing Abs against influenza (H5N1) over t0..
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Figure 3: Humoral response against vaccine preparation and influenza virus (H5N1) before (t0) and after (t1) seasonal influenza vaccination. Hemagglutination inhibition (HI) test was used to calculate the antibody (Ab) titer against vaccine preparation (top panel), whereas a neutralization test was used to calculate the antibody titer against influenza (H5N1) (bottom panel) in healthy donors enrolled in the study at baseline (t0) and 1 month after seasonal influenza vaccination (t1). At baseline (white bars), all donors had a detectable level of human influenza antibodies. At t1 (black bars), 28 donors (73.6%) (indicated by *) showed a >4 fold increase of Ab titer against vaccine preparation (HI) over t0. After seasonal influenza vaccination, 13 serum samples (33.3%) (indicated by *) from the study population showed a 20-fold increase of neutralizing Abs against influenza (H5N1) over t0..

Mentions: Human sera from the same donors were tested for HI activity against both vaccine and influenza (H5N1) preparations and for neutralization activity against influenza virus (H5N1). Individual titers are reported in Figure 3. A 4-fold rise in HA antibody titer is considered noteworthy, and after vaccination most donors (28/38; 73.7%) showed a noteworthy rise of HI titers against vaccine preparation, as indicated by an asterisk (Figure 3, top panel, black bars). HI titers against influenza (H5N1) remained at undetectable levels after seasonal vaccination (data not shown), but a rise of neutralization titer >20-fold over baseline was observed in 13 (34.2%) of 38 donors (Figure 3, bottom panel, asterisk). All but 1 study participant also responded to seasonal vaccination by a rise in HI titers against vaccine preparation. One donor (21) showed high titers against the H5N1 subtype in NT but a low HI titer against vaccine, a unique situation in the study population. However, antibodies to both anti–influenza (H5N1) and influenza vaccine are raised by vaccination. Our findings indicate that seasonal vaccination can raise neutralizing immunity against influenza (H5N1) virus, which shows the existence of an antibody-dependent cross-type immunity. No correlation between influenza-specific CD4 T cells and humoral responses was observed, which suggests that this type of antibody response was mainly CD4 T-cell independent.


Cross-subtype immunity against avian influenza in persons recently vaccinated for influenza.

Gioia C, Castilletti C, Tempestilli M, Piacentini P, Bordi L, Chiappini R, Agrati C, Squarcione S, Ippolito G, Puro V, Capobianchi MR, Poccia F - Emerging Infect. Dis. (2008)

Humoral response against vaccine preparation and influenza virus (H5N1) before (t0) and after (t1) seasonal influenza vaccination. Hemagglutination inhibition (HI) test was used to calculate the antibody (Ab) titer against vaccine preparation (top panel), whereas a neutralization test was used to calculate the antibody titer against influenza (H5N1) (bottom panel) in healthy donors enrolled in the study at baseline (t0) and 1 month after seasonal influenza vaccination (t1). At baseline (white bars), all donors had a detectable level of human influenza antibodies. At t1 (black bars), 28 donors (73.6%) (indicated by *) showed a >4 fold increase of Ab titer against vaccine preparation (HI) over t0. After seasonal influenza vaccination, 13 serum samples (33.3%) (indicated by *) from the study population showed a 20-fold increase of neutralizing Abs against influenza (H5N1) over t0..
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2600140&req=5

Figure 3: Humoral response against vaccine preparation and influenza virus (H5N1) before (t0) and after (t1) seasonal influenza vaccination. Hemagglutination inhibition (HI) test was used to calculate the antibody (Ab) titer against vaccine preparation (top panel), whereas a neutralization test was used to calculate the antibody titer against influenza (H5N1) (bottom panel) in healthy donors enrolled in the study at baseline (t0) and 1 month after seasonal influenza vaccination (t1). At baseline (white bars), all donors had a detectable level of human influenza antibodies. At t1 (black bars), 28 donors (73.6%) (indicated by *) showed a >4 fold increase of Ab titer against vaccine preparation (HI) over t0. After seasonal influenza vaccination, 13 serum samples (33.3%) (indicated by *) from the study population showed a 20-fold increase of neutralizing Abs against influenza (H5N1) over t0..
Mentions: Human sera from the same donors were tested for HI activity against both vaccine and influenza (H5N1) preparations and for neutralization activity against influenza virus (H5N1). Individual titers are reported in Figure 3. A 4-fold rise in HA antibody titer is considered noteworthy, and after vaccination most donors (28/38; 73.7%) showed a noteworthy rise of HI titers against vaccine preparation, as indicated by an asterisk (Figure 3, top panel, black bars). HI titers against influenza (H5N1) remained at undetectable levels after seasonal vaccination (data not shown), but a rise of neutralization titer >20-fold over baseline was observed in 13 (34.2%) of 38 donors (Figure 3, bottom panel, asterisk). All but 1 study participant also responded to seasonal vaccination by a rise in HI titers against vaccine preparation. One donor (21) showed high titers against the H5N1 subtype in NT but a low HI titer against vaccine, a unique situation in the study population. However, antibodies to both anti–influenza (H5N1) and influenza vaccine are raised by vaccination. Our findings indicate that seasonal vaccination can raise neutralizing immunity against influenza (H5N1) virus, which shows the existence of an antibody-dependent cross-type immunity. No correlation between influenza-specific CD4 T cells and humoral responses was observed, which suggests that this type of antibody response was mainly CD4 T-cell independent.

Bottom Line: Avian influenza virus (H5N1) can be transmitted to humans, resulting in a severe or fatal disease.No correlation between influenza-specific CD4 T cells and humoral responses was observed.N1 may possibly be a target for both cellular and humoral cross-type immunity, but additional experiments are needed to clarify this point.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Virology, National Institute for Infectious Diseases Lazzaro Spallanzani, Istituti di Ricovero e Cura a Carattere Scientifico, Via Portuense 292, Rome, Italy.

ABSTRACT
Avian influenza virus (H5N1) can be transmitted to humans, resulting in a severe or fatal disease. The aim of this study was to evaluate the immune cross-reactivity between human and avian influenza (H5N1) strains in healthy donors vaccinated for seasonal influenza A (H1N1)/(H3N2). A small frequency of CD4 T cells specific for subtype H5N1 was detected in several persons at baseline, and seasonal vaccine administration enhanced the frequency of such reactive CD4 T cells. We also observed that seasonal vaccination is able to raise neutralizing immunity against influenza (H5N1) in a large number of donors. No correlation between influenza-specific CD4 T cells and humoral responses was observed. N1 may possibly be a target for both cellular and humoral cross-type immunity, but additional experiments are needed to clarify this point. These findings highlight the possibility of boosting cross-type cellular and humoral immunity against highly pathogenic avian influenza A virus subtype H5N1 by seasonal influenza vaccination.

Show MeSH
Related in: MedlinePlus