Frequency of Measles Virus-Specific CD4+ and CD8+ T Cells in Subjects Seronegative or Highly Seropositive for Measles Vaccine

ABSTRACT The protective effect of measles immunization is due to humoral and cell-mediated immune responses. Little is known about cell-mediated immunity (CMI) to measles vaccine virus, the relative contribution of CD4+ and CD8+ T cells to variability in such immune responses, and the immunologic longevity of the CMI after measles vaccination in humans. Our study characterizes cellular immune response in subjects seronegative or highly seropositive for measles vaccine immunoglobulin G-specific antibody, aged 15 to 25 years, previously immunized with two doses of measles-mumps-rubella II vaccine. We evaluated the ability of subjects to respond to measles vaccine virus by measuring measles virus-specific T-cell proliferation. We examined the frequencies of measles virus-specific memory Th1 and Th2 cells by an ELISPOT assay. Our results demonstrated that proliferation of T cells in seronegative subjects was significantly lower than that for highly seropositive subjects (P = 0.003). Gamma interferon (IFN-γ) secretion predominated over interleukin 4 (IL-4) secretion in response to measles virus in both groups. The median frequency of measles virus-reactive CD8+ T cells secreting IFN-γ was 0.09% in seronegative subjects and 0.43% in highly seropositive subjects (P = 0.04). The median frequency of CD4+ T cells secreting IL-4 in response to measles virus was 0.03% in seronegative subjects and 0.09% in highly seropositive subjects (P = 0.005). These data confirm the presence of measles virus-specific cellular immune responses post-measles vaccine immunization in humans. The detection of measles virus-induced IFN-γ and IL-4 production by ELISPOT can be used to identify measles virus-specific low-frequency memory T cells in subjects immunized with measles vaccine. These differences agree in directionality with the observed antibody response phenotype.

Download Full-text

Molecular and Immunological Significance of Chimpanzee Major Histocompatibility Complex Haplotypes for Hepatitis C Virus Immune Response and Vaccination Studies

Journal of Virology ◽

10.1128/jvi.76.12.6093-6103.2002 ◽

2002 ◽

Vol 76 (12) ◽

pp. 6093-6103 ◽

Cited By ~ 22

Author(s):

Eishiro Mizukoshi ◽

Michelina Nascimbeni ◽

Joshua B. Blaustein ◽

Kathleen Mihalik ◽

Charles M. Rice ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Major Histocompatibility Complex ◽

Hepatitis C ◽

Immune Responses ◽

Cellular Immune Responses ◽

Functional Homology ◽

Histocompatibility Complex ◽

Ifn Γ ◽

Cellular Immune

ABSTRACT The chimpanzee is a critical animal model for studying cellular immune responses to infectious pathogens such as hepatitis B and C viruses, human immunodeficiency virus, and malaria. Several candidate vaccines and immunotherapies for these infections aim at the induction or enhancement of cellular immune responses against viral epitopes presented by common human major histocompatibility complex (MHC) alleles. To identify and characterize chimpanzee MHC class I molecules that are functionally related to human alleles, we sequenced 18 different Pan troglodytes (Patr) alleles of 14 chimpanzees, 2 of them previously unknown and 3 with only partially reported sequences. Comparative analysis of Patr binding pockets and binding assays with biotinylated peptides demonstrated a molecular homology between the binding grooves of individual Patr alleles and the common human alleles HLA-A1, -A2, -A3, and -B7. Using cytotoxic T cells isolated from the blood of hepatitis C virus (HCV)-infected chimpanzees, we then mapped the Patr restriction of these HCV peptides and demonstrated functional homology between the Patr-HLA orthologues in cytotoxicity and gamma interferon (IFN-γ) release assays. Based on these results, 21 HCV epitopes were selected to characterize the chimpanzees' cellular immune response to HCV. In each case, IFN-γ-producing T cells were detectable in the blood after but not prior to HCV infection and were specifically targeted against those HCV peptides predicted by Patr-HLA homology. This study demonstrates a close functional homology between individual Patr and HLA alleles and shows that HCV infection generates HCV peptides that are recognized by both chimpanzees and humans with Patr and HLA orthologues. These results are relevant for the design and evaluation of vaccines in chimpanzees that can now be selected according to the most frequent human MHC haplotypes.

Download Full-text

Comparative analysis of cellular immune responses in conventional and SPF Baboons (Papio spp.)

10.1101/455881 ◽

2018 ◽

Author(s):

Elizabeth R Magden ◽

Bharti P. Nehete ◽

Sriram Chitta ◽

Lawrence E. Williams ◽

Joe H Simmons ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Lymphocyte Subsets ◽

Effector Memory ◽

Peripheral Blood Mononuclear ◽

Phenotypic Differences ◽

Successful Model ◽

Specific Pathogen ◽

Ifn Γ ◽

Cellular Immune

AbstractBaboons (papio spp.) have served as a successful model of human disease such as cardiac and respiratory, infectious, diabetes, genetics, immunology, aging, and xenotransplantation. The development of an immunologically defined specific-pathogen free (SPF) baboon model has further advanced research, especially with studies involving the immune system and immunosuppression. In this study, we compare normal immunological changes of peripheral blood mononuclear cell (PBMC) subsets, and their function in age-matched conventional and SPF baboons. Our results demonstrate that both groups have comparable numbers of different lymphocyte subsets, but there are phenotypic differences in central and effector memory T cells subsets that are more pronounced in the CD4+ T cells. Despite equal proportions of CD3+ T cells among the conventional and SPF baboon groups, PBMC show higher proliferative responses to mitogens PHA and PWM and higher IFN-γ producing cells to Con A and PWM in the conventional group. Plasma levels of the inflammatory cytokine TNF-α were significantly higher in SPF baboons. Exposure of PBMC from conventional baboons to various Toll like ligands (TLR ligands) TLR-3, TLR-4 and TLR-8 show higher IFN-γ producing cells while PBMC from SPF baboons stimulated with TLR-5 and TLR-6 ligand show higher IFN-γ producing cells. These findings suggest that while the lymphocyte subsets in conventional and SPF baboons share many phenotypic and functional similarities, specific differences exist in immune function of lymphocytes which could impact the quality and quantity of innate and adaptive immune responses. These differences should be considered for better experimental outcomes, specifically in studies measuring immunological endpoints.

Download Full-text

Strain-Dependent Cellular Immune Responses in Cattle following Escherichia coli O157:H7 Colonization

Infection and Immunity ◽

10.1128/iai.02462-14 ◽

2014 ◽

Vol 82 (12) ◽

pp. 5117-5131 ◽

Cited By ~ 21

Author(s):

Alexander Corbishley ◽

Nur Indah Ahmad ◽

Kirsty Hughes ◽

Michael R. Hutchings ◽

Sean P. McAteer ◽

...

Keyword(s):

Escherichia Coli ◽

T Cells ◽

Immune Responses ◽

Vaccine Development ◽

Phage Type ◽

Γδ T Cells ◽

Cellular Immune Responses ◽

Ifn Γ ◽

Cellular Immune ◽

Strain Dependent

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) O157:H7 causes hemorrhagic diarrhea and potentially fatal renal failure in humans. Ruminants are considered to be the primary reservoir for human infection. Vaccines that reduce shedding in cattle are only partially protective, and their underlying protective mechanisms are unknown. Studies investigating the response of cattle to colonization generally focus on humoral immunity, leaving the role of cellular immunity unclear. To inform future vaccine development, we studied the cellular immune responses of cattle during EHEC O157:H7 colonization. Calves were challenged either with a phage type 21/28 (PT21/28) strain possessing the Shiga toxin 2a (Stx2a) and Stx2c genes or with a PT32 strain possessing the Stx2c gene only. T-helper cell-associated transcripts at the terminal rectum were analyzed by reverse transcription-quantitative PCR (RT-qPCR). Induction of gamma interferon (IFN-γ) and T-bet was observed with peak expression of both genes at 7 days in PT32-challenged calves, while upregulation was delayed, peaking at 21 days, in PT21/28-challenged calves. Cells isolated from gastrointestinal lymph nodes demonstrated antigen-specific proliferation and IFN-γ release in response to type III secreted proteins (T3SPs); however, responsiveness was suppressed in cells isolated from PT32-challenged calves. Lymph node cells showed increased expression of the proliferation marker Ki67 in CD4+T cells from PT21/28-challenged calves, NK cells from PT32-challenged calves, and CD8+and γδ T cells from both PT21/28- and PT32-challenged calves followingex vivorestimulation with T3SPs. This study demonstrates that cattle mount cellular immune responses during colonization with EHEC O157:H7, the temporality of which is strain dependent, with further evidence of strain-specific immunomodulation.

Download Full-text

Stimulation of Dendritic Cells via CD40 Enhances Immune Responses to Mycobacterium tuberculosisInfection

Infection and Immunity ◽

10.1128/iai.69.4.2456-2461.2001 ◽

2001 ◽

Vol 69 (4) ◽

pp. 2456-2461 ◽

Cited By ~ 43

Author(s):

Caroline Demangel ◽

Umaimainthan Palendira ◽

Carl G. Feng ◽

Andrew W. Heath ◽

Andrew G. D. Bean ◽

...

Keyword(s):

T Cells ◽

Dendritic Cells ◽

Immune Responses ◽

Protective Efficacy ◽

Interleukin 12 ◽

Ifn Γ ◽

Cellular Immune ◽

Stimulation Of

ABSTRACT The resolution of pulmonary tuberculosis (TB) critically depends on the development of the Th1 type of immune responses, as exemplified by the exacerbation of TB in IL-12-deficient mice. Therefore, vaccination strategies optimizing IL-12 production by antigen-presenting cells (APC) in response to mycobacteria may have enhanced protective efficacy. Since dendritic cells (DC) are the critical APC for activation of CD4+ and CD8+ T cells, we examined whether stimulation of Mycobacterium bovis bacillus Calmette Guérin (BCG)-infected DC via CD40 increased their ability to generate Th1-oriented cellular immune responses. Incubation of DC with an agonistic anti-CD40 antibody activated CD40 signaling in DC, as shown by increased expression of major histocompatibility complex class II and costimulatory molecules, mRNA production for proinflammatory cytokines and interleukin 12 (IL-12) p40. This activation pattern was maintained when DC were stimulated with anti-CD40 antibody and infected with BCG. Importantly, CD40-stimulated BCG-infected DC displayed increased capacity to release bioactive IL-12 and to activate gamma interferon (IFN-γ) producing T cells in vitro. Moreover, when C57BL/6 mice were immunized with these DC and challenged with aerosol Mycobacterium tuberculosis, increased levels of mRNA for IL-12 p40, IL-18, and IFN-γ were present in the draining mediastinal lymph nodes. However, the mycobacterial burden in the lungs was not reduced compared to that in mice immunized with BCG-infected non-CD40-stimulated DC. Therefore, although the manipulation of DC via CD40 is effective for enhancing immune responses to mycobacteria in vivo, additional strategies are required to increase protection against virulent M. tuberculosis infection.

Download Full-text

A novel sensitive approach for frequency analysis of measles virus-specific memory T-lymphocytes in healthy adults with a childhood history of natural measles

Microbiology ◽

10.1099/0022-1317-81-5-1313 ◽

2000 ◽

Vol 81 (5) ◽

pp. 1313-1319 ◽

Cited By ~ 39

Author(s):

Ralph Nanan ◽

Andrea Rauch ◽

Eckhart Kämpgen ◽

Stefan Niewiesk ◽

Hans Wolfgang Kreth

Keyword(s):

T Cells ◽

T Cell ◽

Measles Virus ◽

T Cell Responses ◽

Healthy Adults ◽

Cell Mediated Immunity ◽

Median Frequency ◽

Cell Responses ◽

Specific Memory ◽

History Of

Measles virus (MV), a single-stranded negative-sense RNA virus, is an important pathogen causing almost 1 million deaths annually. Acute MV infection induces immunity against disease throughout life. The immunological factors which are responsible for protection against measles are still poorly understood. However, T-cell-mediated immune responses seem to play a central role. The emergence of new single-cell methods for quantification of antigen-specific T-cells directly ex vivo has prompted us to measure frequencies of MV-specific memory T-cells. As an indicator for T-cell activation IFN-γ production was measured. PBMC were analysed by intracellular staining and ELISPOT assay after stimulation with MV-infected autologous B-lymphoblastoid cell lines or dendritic cells. T-cell responses were exclusively seen with PBMC from MV-seropositive healthy adults with a history of natural measles in childhood. The median frequency of MV-specific T-cells was 0·35% for CD3+CD4+ and 0·24% for the CD3+CD8+ T-cell subset. These frequencies are comparable with T-cell numbers reported by other investigators for persistent virus infections such as Epstein–Barr virus, cytomegalovirus or human immunodeficiency virus. Hence, this study illustrates that MV-specific CD4+ and CD8+ T-cells are readily detectable long after the acute infection, and thus are probably contributing to long-term immunity. Furthermore, this new approach allows efficient analysis of T-cell responses from small samples of blood and could therefore be a useful tool to further elucidate the role of cell-mediated immunity in measles as well as in other viral infections.

Download Full-text

In Vivo Priming of Cd4 T Cells That Produce Interleukin (Il)-2 but Not IL-4 or Interferon (Ifn)-γ, and Can Subsequently Differentiate into IL-4–Or IFN-γ–Secreting Cells

Journal of Experimental Medicine ◽

10.1084/jem.194.8.1069 ◽

2001 ◽

Vol 194 (8) ◽

pp. 1069-1080 ◽

Cited By ~ 91

Author(s):

Xiaowen Wang ◽

Tim Mosmann

Keyword(s):

T Cells ◽

Immune Responses ◽

Cd4 T Cells ◽

Transforming Growth Factor ◽

Cell Receptor ◽

Th2 Cells ◽

Effector Cells ◽

Ifn Γ

The differentiation of antigen-stimulated naive CD4 T cells into T helper (Th)1 or Th2 effector cells can be prevented in vitro by transforming growth factor (TGF)-β and anti–interferon (IFN)-γ. These cells proliferate and synthesize interleukin (IL)-2 but not IFN-γ or IL-4, and can differentiate into either Th1 or Th2 cells. We have now used two-color Elispots to reveal substantial numbers of primed cells producing IL-2 but not IL-4 or IFN-γ during the Th1- or Th2-biased immune responses induced by soluble proteins or with adjuvants. These cells were CD4+CD44high and were present during immediate and long-term immune responses of normal mice. Naive T cell receptor for antigen (TCR) transgenic (DO11.10) T cells were primed in vivo after adoptive transfer into normal hosts and FACS® cloned under conditions that did not allow further differentiation. After clonal proliferation, aliquots of each clone were cultured in Th1- or Th2-inducing conditions. Many in vivo–primed cells were uncommitted, secreting IL-2 but not IL-4 or IFN-γ at the first cloning step, but secreting either IL-4 or IFN-γ after differentiation in the appropriate conditions. These in vivo-primed, uncommitted, IL-2–producing cells may constitute an expanded pool of antigen-specific cells that provide extra flexibility for immune responses by differentiating into Th1 or Th2 phenotypes later during the same or subsequent immune responses.

Download Full-text

Maternal and Foetal Cellular Immune Responses in Dams Infected With High- and Low- Virulence Isolates of Neospora caninum at Mid-Gestation

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.684670 ◽

2021 ◽

Vol 11 ◽

Author(s):

Marta García-Sánchez ◽

Laura Jiménez-Pelayo ◽

Patricia Vázquez ◽

Pilar Horcajo ◽

Javier Regidor-Cerrillo ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Cd8 T Cells ◽

Mononuclear Cells ◽

Neospora Caninum ◽

Response Dynamics ◽

Peripheral Blood Mononuclear ◽

Cellular Immune Responses ◽

Ifn Γ ◽

Cellular Immune

Bovine neosporosis is currently considered one of the main causes of abortion in cattle worldwide and the outcome of the infection is, in part, determined by Neospora caninum isolate virulence. However, the dam and foetal immune responses associated with this factor are largely unknown. We used a model of bovine infection at day 110 of gestation to study the early infection dynamics (10- and 20-days post-infection, dpi) after experimental challenge with high- and low-virulence isolates of N. caninum (Nc-Spain7 and Nc-Spain1H, respectively). In the present work, dam peripheral cellular immune responses were monitored twice a week from -1 to 20 dpi. At different time points, IFN-γ and IL-4 production was investigated in stimulated dam blood and the percentage of monocytes, NK cells, B cells and T cells (CD4+, CD8+ and γδ) in peripheral blood mononuclear cells (PBMC) were determined by flow cytometry. In addition, maternal iliofemoral lymph nodes and foetal spleen and thymus were collected at 10 and 20 dpi for the study of the same cell subpopulations. Peripheral immune response dynamics were similar after the infection with both isolates, with a significant increase in the percentage of CD4+ T cells at 6 and 9 dpi in PBMC, coincident with the higher levels of IFN-γ and IL-4 release. However, the levels of IFN-γ were significantly higher and an increase in CD8+ T cells at 9, 13 and 20 dpi was observed in the dams infected with Nc-Spain7. Nc-Spain1H infection induced higher IL4 levels in stimulated blood and a higher CD4+/CD8+ ratio in PBMC. The analysis of the maternal iliofemoral lymph node showed a significant enhancement in the percentage of NK, CD4+ and CD8+ T cells for the animals infected with the highly virulent isolate and euthanized at 20 dpi. Regarding the foetal responses, the most remarkable result was an increase in the percentage of monocytes at 20 dpi in the spleen of foetuses from both infected groups, which suggests that foetuses were able to respond to N. caninum infection at mid gestation. This work provides insights into how isolate virulence affects the maternal and foetal immune responses generated against N. caninum, which may influence the course of infection.

Download Full-text

Adenovirus Vector Harboring the HBcAg and Tripeptidyl Peptidase II Genes Induces Potent Cellular Immune Responses In Vivo

Cellular Physiology and Biochemistry ◽

10.1159/000456579 ◽

2017 ◽

Vol 41 (2) ◽

pp. 423-438 ◽

Cited By ~ 2

Author(s):

Quanhui Tan ◽

Siyuan Ma ◽

Jianjun Hu ◽

Xiaohua Chen ◽

Yongsheng Yu ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Hepatitis B ◽

Transgenic Mice ◽

Immune Responses ◽

Cellular Immune Response ◽

Specific Cellular Immune Response ◽

Ifn Γ ◽

Cellular Immune

Background: Chronic hepatitis B virus (HBV) infection is associated with a weak but specific cellular immune response of the host to HBV. Tripeptidyl peptidaseⅡ (TPPⅡ), an intracellular macromolecule and proteolytic enzyme, plays an important complementary and compensatory role for the proteasome during viral protein degradation and major histocompatibility complex class I antigen presentation by inducing a specific cellular immune response in vivo. Based on a previous study, we aimed to explore the role of MHC class I antigen presentation in vivo and the mechanisms that may be involved. Methods: In this study, recombinant adenoviral vectors harboring the hepatitis B core antigen (HBcAg) and the TPPII gene were constructed (Adv-HBcAg and Adv-HBcAg-TPPII), and H-2Kd HBV-transgenic BALB/c mice and HLA-A2 C57BL/6 mice were immunized with these vectors, respectively. We evaluated the specific immune responses induced by Adv-HBcAg-TPPII in the HBV transgenic BALB/c mice and HLA-A2 C57BL/6 mice as well as the anti-viral ability of HBV transgenic mice, and we explored the underlying mechanisms. Results: We found that immunization with Adv-HBcAg-TPPII induced the secretion of the cytokines interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) as well as the activities of IFN-γ-secreting CD8+ T cells and CD4+ T cells. In addition, HBcAg-specific CTL activity in C57/BL mice and HBV transgenic animals was significantly enhanced in the Adv-HBcAg-TPPII group. Furthermore, Adv-HBcAg-TPPII decreased the hepatitis B surface antigen (HBsAg) and HBV DNA levels and the amount of HBsAg and HBcAg in liver tissues. Moreover, Adv-HBcAg-TPPII enhanced the expression of T-box transcription factor (T-bet) and downregulated GATA-binding protein 3 (GATA-3) while increasing the expression levels of JAK2, STAT1, STAT4 and Tyk2. Conclusions: These results suggested that the JAK/STAT signaling pathway participates in the CTL response that is mediated by the adenoviral vector encoding TPPII. Adv-HBcAg-TPPII could therefore break immune tolerance and stimulate HBV-specific cytotoxic T lymphocyte activity and could have a good therapeutic effect in transgenic mice.

Download Full-text

Cellular Immune Responses in Children and Adults Receiving Inactivated or Live Attenuated Influenza Vaccines

Journal of Virology ◽

10.1128/jvi.01460-06 ◽

2006 ◽

Vol 80 (23) ◽

pp. 11756-11766 ◽

Cited By ~ 231

Author(s):

Xiao-Song He ◽

Tyson H. Holmes ◽

Caiqiu Zhang ◽

Kutubuddin Mahmood ◽

George W. Kemble ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Influenza Vaccine ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Vaccines ◽

Cellular Immune Responses ◽

Ifn Γ ◽

The Mean ◽

Cellular Immune

ABSTRACT The patterns of cellular immune responses induced by live attenuated influenza vaccine (LAIV) versus those of the trivalent inactivated influenza vaccine (TIV) have not been studied extensively, especially in children. The goals of this study were to evaluate the effects of TIV and LAIV immunization on cellular immunity to live influenza A virus in children and adults and to explore factors associated with variations in responses to influenza vaccines among individuals. A gamma interferon (IFN-γ) flow cytometry assay was used to measure IFN-γ-producing (IFN-γ+) NK and T cells in peripheral blood mononuclear cell cultures stimulated with a live influenza A virus strain before and after LAIV or TIV immunization of children and adults. The mean percentages of influenza A virus-specific IFN-γ+ CD4 and CD8 T cells increased significantly after LAIV, but not TIV, immunization in children aged 5 to 9 years. No increases in the mean levels of influenza A virus-reactive IFN-γ+ T cells and NK cells were observed in adults given LAIV or TIV. TIV induced a significant increase in influenza A virus-reactive T cells in 6-month- to 4-year-old children; LAIV was not evaluated in this age group. The postvaccination changes (n-fold) in the percentages of influenza A virus-reactive IFN-γ+ T and NK cells in adults were highly variable and correlated inversely with the prevaccination percentages, in particular with that of the CD56dim NK cell subset. In conclusion, our findings identify age, type of vaccine, and prevaccination levels of immune reactivity to influenza A virus as factors significantly associated with the magnitude of cellular immune responses to influenza vaccines.

Download Full-text

Development and Validation of a Gamma Interferon ELISPOT Assay for Quantitation of Cellular Immune Responses to Varicella-Zoster Virus

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.5.871-879.2001 ◽

2001 ◽

Vol 8 (5) ◽

pp. 871-879 ◽

Cited By ~ 103

Author(s):

Jeffrey G. Smith ◽

Xu Liu ◽

Robin M. Kaufhold ◽

James Clair ◽

Michael J. Caulfield

Keyword(s):

T Cells ◽

Immune Responses ◽

Varicella Zoster Virus ◽

Liquid Nitrogen ◽

Elispot Assay ◽

Gamma Interferon ◽

Cell Mediated Immunity ◽

Varicella Zoster ◽

Cellular Immune Responses ◽

Cellular Immune

ABSTRACT Cell-mediated immunity appears to be critical for the prevention and control of varicella-zoster virus (VZV) infection and complications arising from zoster. Current assays of VZV-specific cell-mediated immunity are cumbersome or lack sensitivity. We have developed a gamma interferon ELISPOT assay that provides a direct measure of the number of T cells secreting a cytokine following stimulation with antigen. This assay is extremely sensitive and specific, with the ability to detect gamma interferon spot-forming cells (SFC) in the range of 10 to 1,000 SFC per million peripheral blood mononuclear cells (PBMCs). This assay has been validated by demonstrating the following: (i) the response detected is mediated almost entirely by CD4+ T cells, (ii) ELISPOT responses from fresh-frozen PBMCs are equivalent to those from freshly isolated cells, (iii) frozen PBMCs can be shipped on dry ice for up to 48 h without loss of activity, (iv) frozen PBMC samples can be stored in liquid nitrogen over long periods (>22 months) without any significant change in response, and (v) the numbers of ELISPOTs counted using a computer-based imaging system are equivalent to those counted by humans but have lower variability. The ability to use frozen cells is facilitated by the use of a recombinant nuclease (Benzonase) that can prevent cell clumping when samples are thawed. Frozen PBMC samples can be cycled through multiple changes in storage between liquid nitrogen and dry ice without any change in response being detected. This facilitates collection of samples at one site and testing performed at a remote location. This VZV ELISPOT assay provides a new versatile tool for monitoring cellular immune responses either during a herpes zoster disease outbreak or following vaccination.

Download Full-text