Influenza-specific Antibody Secreting Cells Research Articles

SAT-317 INFLEUNZA VACCINATION RECALL IMMUNE RESPONSES QUANTIFICATION IN CHIMERIC RENAL TRANSPLANT RECEIPITS AT A SINGLE CELL LEVEL & HIA

Drug-based immunosuppression significantly increases the risk of infection and cancer. Development of new approaches to minimize or eliminate graft rejection is of great interest to the transplant community. Establishment of durable hematopoietic chimerism through hematopoietic stem cell transplantation (HSCT) has been shown in preclinical models and patients to lead to donor specific tolerance. Those chimeric patients immune competence to virus infection never been investigated. Herein, we investigated the recall immune responses in a series of chimeric renal transplant recipients received CD8+/TCR- facilitating cell-based hematopoietic stem cell transplant (termed FCRx) to induce tolerance to mismatched renal allografts. This study took advantage of recent breakthroughs in the single-cell quantification of human peripheral blood B-cell responses to prospectively evaluate both B- and T-cell responses to the seasonal influenza vaccine (A/California[H1N1], A/SWIZERLAND [H3N2], B/BRISBANE, B/PHUKET] at day 0 before vaccination and day 30 post vaccination in 3 chimeric renal transplant recipients (proved by HLA PCR], and 3 healthy controls. Utilizing ELISA, flowcytometry analysis of T & B phenotypes, intracellular IFN-Y, B-cell culture supernatant and haemaggultination inhibition assay. there was a significant overall B-cell response to influenza vaccination, quantified by the frequency of influenza-specific antibody-secreting cells (ASC) in peripheral blood of chimeric patients but the magnitude was significantly reduced compared to healthy controls. The magnitude of the sero-response and the rate of sero-conversion were also blunted. The influenza-specific interferon-gamma (IFNγ) T-cell response was significantly reduced in transplant recipients; however, there was no correlation between the magnitude of the influenza specific IgG ASC, IFNγ responses and HIA. The induction of memory T- and B-cell responses to influenza vaccination supports the recommendation to vaccinate while the blunted responses in chimeric transplant patients.

Plasma cell and serum antibody responses to influenza vaccine in preterm and full-term infants.

Preterm (PT) infants are at greater risk for severe influenza infection and experience decrements in long-term antibody responses to vaccines. This may related to defects in antibody secreting cell (ASC) generation. To investigate the relationships among the frequencies of influenza-specific antibody secreting cells, ASC numbers and subsets, and antibody responses to influenza vaccines (IV) among PT and full-term (FT) infants. We enrolled 11 former PT (≤32weeks' gestation, ≤1500 g' birth weight) and 11FT infants, 6-17months of age, receiving their first influenza immunizations. Infants received two doses of inactivated trivalent (T)IV or quadrivalent (Q)IV during the 2012-2013 and 2013-2014 influenza seasons, respectively, at 0 and 28days, and blood was drawn at 0, 10, 35, and 56days and 9months. Vaccine-specific antibody was measured by hemagglutination inhibition (HAI) at 0 and 56days and 9months, vaccine-specific ASC numbers by enzyme linked immunospot (ELISPOT) at 10 and 35days, and ASC subsets by flow cytometry at 0, 10 and 35days. PT infants had post-vaccine HAI titers to all 4 vaccine strains at least equal to FT infants at 56days and 9months after beginning immunization. Influenza-specific ASC ELISPOT responses at 35days were higher among PT than FT infants (median 100 v. 30 per 106 PBMC, p=0.04). ASC numbers at 35days were positively correlated with serum HAI titers at 56days (ρ=0.50-0.80). There were no statistical differences between PT and FT infants in the frequency of five ASC subsets and no specific ASC subset correlated with durability of serum antibody titers. Influenza-specific ASC numbers in both FT and PT infants correlated with peak antibody titers, but ASC subsets did not correlate with durability of antibody response.

AS03-Adjuvanted, Very-Low-Dose Influenza Vaccines Induce Distinctive Immune Responses Compared to Unadjuvanted High-Dose Vaccines in BALB/c Mice.

During the 2009–2010 influenza pandemic, an adjuvanted, dose-sparing vaccine was recommended for most Canadians. We hypothesize that differences exist in the responses to AS03-adjuvanted, low antigen (Ag) dose versus unadjuvanted, full-dose vaccines. We investigated the relationship between Ag dose and the oil-in-water emulsion Adjuvant System AS03. BALB/c mice received two IM doses of AS03A or AS03B with exaggerated dilutions of A/Uruguay/716/2007 H3N2 split virion vaccine Ag. Immune responses were assessed 3 weeks after the booster. Unadjuvanted “high” (3 μg) and low-dose (0.03–0.003 μg) vaccines generated similar serum antibody titers and cytokine secretion patterns in restimulated splenocytes. Compared to unadjuvanted “high-dose” vaccination, both AS03A and AS03B-adjuvanted low-dose vaccines tended to elicit higher serum antibody titers, broader induction of cytokine secretion and generated more influenza-specific antibody secreting cells and cytokine-secreting CD4 and CD8 T cells in splenocytes. We show that varying Ag and/or AS03 dose in this influenza vaccination mouse model can strongly influence both the magnitude and pattern of the immune response elicited. These findings are highly relevant given the likelihood of expanded use of adjuvanted, dose-sparing vaccines and raise questions about the use of “standard” doses of vaccines in pre-clinical vaccine studies.

Enhanced immune responses by skin vaccination with influenza subunit vaccine in young hosts

Skin has gained substantial attention as a vaccine target organ due to its immunological properties, which include a high density of professional antigen presenting cells (APCs). Previous studies have demonstrated the effectiveness of this vaccination route not only in animal models but also in adults. Young children represent a population group that is at high risk from influenza infection. As a result, this group could benefit significantly from influenza vaccine delivery approaches through the skin and the improved immune response it can induce. In this study, we compared the immune responses in young BALB/c mice upon skin delivery of influenza vaccine with vaccination by the conventional intramuscular route. Young mice that received 5μg of H1N1 A/Ca/07/09 influenza subunit vaccine using MN demonstrated an improved serum antibody response (IgG1 and IgG2a) when compared to the young IM group, accompanied by higher numbers of influenza-specific antibody secreting cells (ASCs) in the bone marrow. In addition, we observed increased activation of follicular helper T cells and formation of germinal centers in the regional lymph nodes in the MN immunized group, rapid clearance of the virus from their lungs as well as complete survival, compared with partial protection observed in the IM-vaccinated group. Our results support the hypothesis that influenza vaccine delivery through the skin would be beneficial for protecting the high-risk young population from influenza infection.

Impact of Immunosuppression on Recall Immune Responses to Influenza Vaccination in Stable Renal Transplant Recipients

The recommendation by the American Society of Transplantation for annual trivalent inactivated influenza vaccination greater than 3 to 6 months post-kidney transplantation provides a unique opportunity to test the in vivo impact of immunosuppression on recall T- and B-cell responses to influenza vaccination. This study took advantage of recent breakthroughs in the single-cell quantification of human peripheral blood B-cell responses to prospectively evaluate both B- and T-cell responses to the seasonal (2010 and 2011) influenza vaccine in 23 stable renal transplant recipients and 22 healthy controls. The results demonstrate that the early B-cell response to influenza vaccination, quantified by the frequency of influenza-specific antibody-secreting cells (ASC) in peripheral blood, was significantly reduced in stable transplant recipients compared to healthy controls. The magnitude of the seroresponse and the rate of seroconversion were also blunted. The influenza-specific interferon-gamma (IFNγ) T-cell response was significantly reduced in transplant recipients; however, there was no correlation between the magnitude of the influenza-specific IgG ASC and IFNγ responses. The induction of memory T- and B-cell responses to influenza vaccination supports the recommendation to vaccinate while the blunted responses demonstrate the efficacy of immunosuppression in controlling memory responses individual transplant recipients.

Evaluation of the Humoral and Cellular Immune Responses Elicited by the Live Attenuated and Inactivated Influenza Vaccines and Their Roles in Heterologous Protection in Ferrets

The humoral and cellular immune responses elicited by the trivalent live attenuated influenza vaccine (LAIV) and the trivalent inactivated influenza vaccine (TIV) were evaluated in the ferret model, using newly developed ferret immunological reagents and assays. In contrast to the TIV, which only induced immune responses in primed animals, LAIV induced strong influenza virus-specific serum antibody and T-cell responses in both naive and influenza-seropositive animals. The LAIV offered significant protection against a heterologous H1N1 virus challenge infection in the upper respiratory tract. Influenza virus-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) antibody-secreting cells (ASCs) and influenza virus-specific CD4(+) and CD8(+) T cells were detected in the circulation and local paratracheal draining lymph nodes. The frequency of the influenza-specific ASCs in the local lymph nodes appeared to correlate with the degree of protection in the upper respiratory tract. The protection conferred by the LAIV could be attributed not only to the antibody response but also to the cell-mediated and local mucosal immune responses, particularly in naive ferrets. These findings may explain why the LAIV is immunologically superior and offers immediate protection after a single dose in children.

Pandemic Influenza Vaccination Elicits Influenza‐Specific CD4+ Th1‐cell Responses in Hypogammaglobulinaemic Patients: Four case reports

In these case reports, we investigated pandemic influenza 2009 vaccination of primary hypogammaglobulinaemic patients. Three combined variable immunodeficiency (CVID) patients and one X-linked agammaglobulinaemia (XLA) patient were vaccinated with the pandemic vaccine A/California/7/2009 (H1N1)-like split virus (X179a) adjuvanted with the oil-in-water emulsion AS03. Subsequently, serum and peripheral blood mononuclear cells were sampled and used to measure the haemagglutination inhibition (HI) and antibody-secreting cell (ASC) responses. In addition, the IFN-γ, IL-2 and TNF-α producing CD4(+) Th1-cell response was determined as these cytokines are important indicators of cell-mediated immunity. Two of the CVID patients responded to vaccination as determined by a >4-fold rise in HI antibodies. These subjects also had influenza-specific ASC numbers, which, albeit low, were higher than prevaccination levels. In addition, vaccination induced CD4(+) Th1-cell responses in both the XLA patient and the CVID patients, although the frequency of influenza-responsive cells varied amongst the patients. These results suggest that hypogammaglobulinaemia patients can mount a CD4(+) Th1 cell-mediated response to influenza vaccination and, additionally, that influenza vaccination of some hypogammaglobulinaemia patients can produce an influenza-specific humoral immune response. The findings should be confirmed in larger clinical studies.

Peak frequencies of circulating human influenza-specific antibody secreting cells correlate with serum antibody response after immunization

Upon vaccination, B cells differentiate into antibody secreting cells (ASCs) that migrate via the circulation to tissues. The kinetics of this response and the relationship of circulating ASCs to protective antibody titers have not been completely explored. Methods Influenza-specific and total-IgG ASCs were enumerated by Elispot and flow cytometry daily in the blood in 6 healthy adults after trivalent influenza vaccination (TIV). Results Peak H1-specific IgG ASC frequencies occurred variably from day 5 to 8 and correlated with the fold-rise rise in hemagglutination inhibition (HAI titers); r = 0.91, p = 0.006. H3-specific IgG ASC frequencies correlated less well, perhaps due to a mismatch of the H3 protein in the vaccine and that used in the Elispot assay. Peak frequencies of vaccine-specific and total-IgG ASCs were 0.3% and 0.8%, respectively, of peripheral blood mononuclear cells (PBMC). Peak TIV-, H1-, H3-, and total-IgG ASC frequencies were 1736 ± 1133, 626 ± 520, 592 ± 463, and 4091 ± 2019 spots/10 6 PBMC, respectively. Peak TIV-, H1-, and H3-specific IgG ASC of total-IgG ASC frequencies constituted 63% ± 21, 26% ± 10, 22% ± 17, respectively. Conclusion After immunization with inactivated influenza vaccine the peak in influenza-specific ASC frequencies is variable but correlates well with the magnitude of protective HAI responses.

A pilot study of the immune response to whole inactivated avian influenza H7N1 virus vaccine in mice

Background Highly pathogenic avian influenza (HPAI) outbreaks in domestic poultry bring humans into close contact with new influenza subtypes and represent a threat to human health. In 1999, an HPAI outbreak of H7N1 virus occurred in domestic poultry in Italy, and a wild‐type virus isolate from this outbreak was chosen as a pandemic vaccine candidate. Objectives We conducted a pilot study to investigate the kinetics of the humoral immune response induced after immunisation with an egg grown whole inactivated H7N1 virus vaccine in BALB/c mice. Methods Mice were vaccinated with one or two doses of H7N1 vaccine (15 μg total protein) to investigate the influenza specific antibody secreting cell (IS‐ASC) and serum antibody responses. Results After the first dose of vaccine, only IgM IS‐ASC were detected in the spleen and bone marrow, whereas IgG, IgA and IgM IS‐ASC were found after the second dose. Low antibody titres were detected after the first immunisation, whilst the second dose of vaccine significantly boosted the HI (range 128–512), neutralising and IgG antibody titres. The IgG subclass response was dominated by IgG2a indicating a dominant Th1 response after the first vaccination, whereas a more mixed Th1/Th2 profile was observed after the second dose. Conclusions This pilot study shows the value of using a number of immunological methods to evaluate the quality of the immune response to potential pandemic candidate vaccines.

Frequencies of human influenza-specific antibody secreting cells or plasmablasts post vaccination from fresh and frozen peripheral blood mononuclear cells

The rise in influenza-specific neutralizing antibody levels is proceeded by a burst of antigen-specific antibody secreting cells (ASC) or plasmablasts identified in peripheral blood approximately 5–10 days post immunization. Blood antigen-specific ASC may function as an immune marker of vaccine responses in comparison to the pre- and post-neutralizing titers; however, some have questioned whether there is adequate survival of ASC isolated from peripheral blood after freezing, making multi-center vaccine trials difficult. Here, we demonstrate similar frequencies of influenza-specific ASC from fresh and frozen peripheral blood mononuclear cells (PBMC). Influenza Hemagglutinin (HA) H1, H3, and H7-specific ASC IgG ELISpots frequencies were compared from the same fresh and frozen PBMC 7 days after 2006 Trivalent Influenza Vaccine (TIV) in 10 young healthy subjects. H1-, H3-, and H7-specific IgG ASC spots/106 from fresh PBMC on day 7 were 229±341, 98±90, and 6±11 respectively. Total IgG ASC spots/million PBMC pre- and 7-day post-vaccination were 290±188 (0.029% PBMC) and 1691±836 (0.17% PBMC) respectively. There was no difference in the H1 -H3-, and total specific ASC IgG ELISpot frequencies from the fresh versus frozen PBMC on day 7 (p=0.43, 0.28, 0.28 respectively). These results demonstrate feasibility of testing whether antigen-specific ASC from frozen PBMC are an early biomarker of long-term antibody responses in multi-center vaccine trials.

Evaluation of Immune Responses to Seasonal Influenza Vaccination in Healthy Volunteers and in Patients After Stem Cell Transplantation

Influenza causes significant morbidity and mortality in immunocompromised stem cell transplantation (SCT) recipients. Measurement of cellular and humoral immunological responses might increase our understanding of how to estimate a protective response to influenza vaccination. Eighteen healthy subjects and 14 SCT patients tested before and 4 weeks after influenza vaccination were included in the study. Peripheral blood lymphocytes were stimulated with influenza peptides and Enzyme-Linked ImmunoSpot assays to measure the production of intracellular interferon-gamma, interleukin-4 and interleukin-13. Prelabeled major histocompatibility complex class I pentamers were used for the detection of influenza-specific CD8+ T-cells. B-cell Enzyme-Linked ImmunoSpot and hemagglutination inhibition assays were performed to enumerate influenza-specific antibody-secreting cells and titer of neutralizing antibodies. Influenza vaccination elicited strong cell-mediated immune responses in the healthy controls (P< or =0.003 for all four peptides) and SCT patients (P< or =0.008). The percentage of CD8+ specific cells increased significantly after vaccination both in volunteers (P=0.005) and in patients (P< or =0.003). The number of influenza-specific antibody-secreting cells increased after vaccination both in volunteers (P=0.009) and in patients (P=0.01). Twenty-nine percent of SCT patients demonstrated protective antibody levels to influenza A H1/N1 serotype. Seasonal vaccination against influenza boosts the cellular immune response both in SCT patients and healthy controls. The protective effect is lower in the patients in general and especially on those, vaccinated early after SCT.

Evaluation of Immune Responses to Seasonal Influenza Vaccination in Healthy Volunteers and in Patients after Stem Cell Transplantation.

Influenza causes significant morbidity and mortality in immunocompromised stem cell transplant (SCT) recipients. Measurement of cellular and humoral immunological responses might increase our understanding of how to estimate a protective response to influenza vaccination. Eighteen healthy subjects and 14 SCT patients tested before and 4 weeks after influenza vaccination were included in the study. Peripheral blood lymphocytes were stimulated with four influenza peptides; three based on sequences from the hemagglutinin and one from the M1 protein. Elispot assays were performed to measure the production of intracellular interferon-gamma (IFN-) and interleukin-13 (IL-13). Pre-labeled MHC class I pentamers were used for the detection of influenza-specific CD8+ T-cells. B-cell Elispot was performed to enumerate influenza-specific antibody-secreting cells (ASCs). Finally, haemagglutination inhibition (HIA) was used to determine the serum titers of neutralizing antibodies. Influenza vaccination elicited strong cell-mediated immune responses in the healthy volunteers (p≤0.003 for all four peptides) and SCT patients (p≤0.008). The percentage of CD8+ influenza-specific cells increased significantly after vaccination of both volunteers (p=0.005) and patients (p≤0.003). The number of influenza-specific ASCs increased as well (in volunteers p=0.009, in patients p=0.01). Only 29% of the SCT patients developed protective antibody levels to the influenza A H1/N1 serotype while no patient had protective antibody levels to H3/N2 or influenza B types. All responses were lower in patients studied less than 6 months after SCT compared to those studied later after SCT. These results indicate that seasonal vaccination against influenza can boost the cellular immune response in SCT patients and healthy controls, while B-cell responses are suboptimal in SCT patients.

The humoral and cellular responses induced locally and systemically after parenteral influenza vaccination in man

Studies of the immune response after influenza vaccination in man, with focus on the immune activity occurring locally at mucosal surfaces and in associated lymphoid tissue, provide a valuable insight into immunity to influenza. The aim of influenza vaccination is to develop immunological memory resulting in enhanced rapid specific response upon subsequent influenza encounter. The tonsils are thought to play an important role as an activating, effector and memory site for immune responses against influenza. We have shown that normally high numbers of influenza-specific antibody secreting cells (ASC) are present in the nasal mucosa of healthy adults but upon parenteral vaccination the numbers remain stable. However, a rapid transient increase in influenza-specific ASC is observed in the tonsils and peripheral blood after vaccination. In the tonsils and blood, parenteral vaccination results in a significant decrease in CD4 + cells upon vaccination, which are probably recruited to the draining lymph node.

Compromised B Cell Responses to Influenza Vaccination in HIV‐Infected Individuals

Yearly influenza vaccination, although recommended for human immunodeficiency virus (HIV)-infected individuals, has not received thorough evaluation in the era of antiretroviral therapy. We assessed the impact of HIV disease on B cell responses to influenza vaccination. Sixty-four HIV-infected and 17 HIV-negative individuals received the 2003-2004 trivalent inactivated influenza vaccine. Frequencies of influenza-specific antibody-secreting cells (ASCs) were measured by enzyme-linked immunospot (ELISPOT) assay, and antibody responses were measured by hemagglutination-inhibition (HI) assay. Memory responses to influenza were measured by ELISPOT assay after polyclonal activation of B cells in vitro. Prevaccination HI titers were significantly higher in HIV-negative than in HIV-infected individuals. Peak HI titers and influenza-specific ASC frequencies were directly correlated with CD4+ T cell counts in HIV-infected individuals. Influenza-specific memory B cell responses were significantly lower in HIV-infected than in HIV-negative individuals and were directly correlated with CD4+ T cell counts. HIV infection is associated with a weak antibody response to influenza vaccination that is compounded by a poor memory B cell response. CD4+ T cell count is a critical determinant of responsiveness to influenza vaccination, and the contribution of plasma HIV RNA level is suggestive and warrants further investigation.

The kinetics of the systemic and local immune response to parenteral influenza vaccination

Studying the humoral immune response after influenza vaccination, with focus on the immune activity occurring locally at mucosal surfaces and in associated lymphoid tissue, provides a valuable tool for understanding immunity to influenza. Here we summarize our work addressing the kinetics of the local and the systemic immune responses after influenza vaccination in humans. Our studies have shown that inactivated influenza vaccine induced a rapid systemic immune response, which was associated with a local response in tonsils and oral fluid in healthy adults. However, the response in tonsils and oral fluid was impaired in young children (under 3 years old). The rapidity and the magnitude of the immune response did not seem to be impaired in diabetic patients and was not altered by treatment of healthy adults with the antiviral zanamivir. High frequencies of influenza-specific antibody secreting cells (ASC) were detected in nasal mucosa of healthy adults. However, parenteral vaccination did not induce an increase in frequency or the number of these ASC. Ongoing studies are investigating the characteristics of influenza-specific T- and B-cells induced locally and systemically after vaccination in man.

Lymphocyte distribution in the tonsils prior to and after influenza vaccination

The tonsils, consisting of the adenoid, tubal, palatine and pharyngeal tonsils, form a ring like structure in humans called Waldeyer’s ring. The ring of tonsils is rich in lymphocytes and may play an important role as a reservoir of memory and immune competent cells serving the respiratory tract. The tonsils may also function as an activating and effector site for immune responses against respiratory pathogens. In this study, we have examined histological tissue sections from palatine tonsils for influenza specific antibody secreting cells (ASC) and several cell surface markers, from non-vaccinated and influenza vaccinated subjects. We found an increase in the number of influenza specific ASC in the tonsils of the influenza vaccinated subjects. These ASC was found scattered inside and surrounding the germinal centres, indicating that they may have homed to the tonsils. In addition, we observed a significant decrease in CD4 positive cells in tonsils of vaccinated subjects. Similar trends were also detected for CD45RA and CD45RO positive cells, which were significantly reduced in the vaccinated tonsils. The number of macrophages bearing the CD68 surface marker increased in numbers in vaccinated subjects. This shows that dynamic changes takes place in the tonsils after parenteral influenza vaccination, which may point to an important role of the tonsils in combating respiratory pathogens.

The basal level of influenza specific antibody-secreting cells in healthy subjects

Background: In the absence of true efficacy markers, the serum haemagglutination inhibition titre has been correlated with protection against influenza infection. Serum antibody does not, however, play a direct role in protection against infection. Two important factors that may be involved in protection against influenza infection are the number of influenza specific activated B-cells and the specificity of the secreted antibodies in the epithelial mucosa of the respiratory tract. Methods: Nineteen patients scheduled for tonsillectomy were enrolled in this study. Tonsils, blood, saliva and a biopsy from the inferior turbinate in the nasal cavity were collected from the patients. None of the patients had been infected or vaccinated with influenza in the previous year. ELISPOT and ELISA assays were used to examine the basal level of antibody-secreting cell (ASC) levels and antibodies in the collected samples, respectively. Results: We found low numbers of influenza specific ASC in the blood and tonsils, but there were much higher numbers of specific ASC in the nasal tissue despite no recent influenza exposure or vaccination. Conclusion: We found antibody-secreting B-cells in the nasal mucosa tissue, which probably results in secretion of specific antibody at the surfaces and protection from influenza infection.

High prevalence of influenza specific antibody secreting cells in nasal mucosa.

Secretory immunoglobulin A (SIgA) provides the first line of defence against pathogens initiating infection via the mucosal route, e.g. the influenza virus. The aim of this study was to examine the basal level of influenza-specific antibody-secreting cell (ASC) in the local mucosa of the upper respiratory tract. Nineteen patients scheduled for tonsillectomy were enrolled for the study, and they had not experienced influenza during the previous year. Tonsils, blood, oral fluid and a nasal biopsy were sampled, and the basal levels of ASC and antibodies (Abs) were determined. We found low numbers of influenza-specific ASC in the blood and tonsils, but there were about 10-100 times higher numbers of specific ASC in the nasal mucosa tissue despite no recent influenza exposure. Thus, the basal level of influenza-specific ASC in the mucosa of the respiratory tract may be important in the protection against influenza infection.

Systemic and local immune responses after parenteral influenza vaccination in juvenile diabetic patients and healthy controls: results from a pilot study

Diabetes patients suffer frequent complications and some excess mortality after influenza virus infection. Despite widespread agreement that diabetic patients should be routinely vaccinated against influenza, some reports claim that diabetics have a poor immune response to influenza vaccine. We have performed a pilot study to examine the humoral immune response of juvenile diabetics and matched healthy controls vaccinated with inactivated trivalent influenza vaccine. By enzyme-linked immunospot assay we found that both groups had comparable magnitude and kinetics of influenza-specific antibody secreting cell response. The influenza-specific antibody response in both serum and oral fluid were similar for both groups, and also showing a kinetic profile in accordance with our earlier data for healthy adults. Our study did not detect a difference in the humoral immune response between juvenile diabetics and healthy controls.

Influenza-specific antibody-secreting cells and B cell memory in the murine lung after immunization with wild-type, cold-adapted variant and inactivated influenza viruses

The development of regional B cell responses was studied in mice immunized intranasally with different influenza virus vaccines. The ca-variant virus was 100-fold less efficient than the parental virus in the induction of influenza virus-specific antibody secreting cells (ASCs) in the lung and failed to induce ASCs in the spleen. The ca-variant virus was also less efficient in priming for secondary IgG and IgA responses generated in vitro in both lung and spleen cell cultures. Protection against homotypic challenge in mice immunized by different vaccine strategies correlated with the development of pulmonary B cell responses rather than splenic responses. In particular, protection correlated with the presence of ASCs and IgG and IgA memory in the lung at the time of challenge.