scholarly journals Infection with Plasmodium berghei Boosts Antibody Responses Primed by a DNA Vaccine Encoding Gametocyte Antigen Pbs48/45

2006 ◽  
Vol 74 (4) ◽  
pp. 2043-2051 ◽  
Author(s):  
Diana Haddad ◽  
Jorge Maciel ◽  
Nirbhay Kumar
Keyword(s):  
Immune Responses ◽  
Dna Vaccine ◽  
Plasmodium Berghei ◽  
Malaria Vaccine ◽  
Natural Infection ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Additional Control ◽  
Antibody Levels ◽  
Repeat Infection

ABSTRACT An important consideration in the development of a malaria vaccine for individuals living in areas of endemicity is whether vaccine-elicited immune responses can be boosted by natural infection. To investigate this question, we used Plasmodium berghei ANKA blood-stage parasites for the infection of mice that were previously immunized with a DNA vaccine encoding the P. berghei sexual-stage antigen Pbs48/45. Intramuscular immunization in mice with one or two doses of DNA-Pbs48/45 or of empty DNA vaccine as control did not elicit detectable anti-Pbs48/45 antibodies as determined by enzyme-linked immunosorbent assay. An infection with P. berghei ANKA 6 weeks after DNA vaccination elicited comparable anti-Pbs48/45 antibody levels in mice which had been primed with DNA-Pbs48/45 or with empty DNA vaccine. However, a repeat infection with P. berghei ANKA resulted in significantly higher anti-Pbs48/45 antibody levels in mice which had been primed with the DNA-Pbs48/45 vaccine than the levels in the mock DNA-vaccinated mice. In parallel and as an additional control to distinguish the boosting of Pbs48/45 antibodies exclusively by gametocytes during infection, a separate group of mice primed with DNA-Pbs48/45 received an infection with P. berghei ANKA clone 2.33, which was previously described as a “nongametocyte producer.” To our surprise, this parasite clone too elicited antibody levels comparable to those induced by the P. berghei gametocyte producer clone. We further demonstrate that the nongametocyte producer P. berghei clone is in fact a defective gametocyte producer that expresses Pbs48/45, much like the gametocyte producer clone, and is therefore capable of boosting antibody levels to Pbs48/45. Taken together, these results indicate that vaccine-primed antibodies can be boosted during repeat infections and warrant further investigation with additional malaria antigens.

scholarly journals Limited Local and Systemic Antibody Responses toNeisseria gonorrhoeae during Uncomplicated Genital Infections

1999 ◽  
Vol 67 (8) ◽  
pp. 3937-3946 ◽  
Author(s):  
Spencer R. Hedges ◽  
Matthew S. Mayo ◽  
Jiri Mestecky ◽  
Edward W. Hook ◽  
Michael W. Russell
Keyword(s):  
Immune Responses ◽  
Transmitted Disease ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Genital Infections ◽  
Sexually Transmitted ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Repeated Infections ◽  
Antibody Levels

ABSTRACT Repeated infections with Neisseria gonorrhoeae are common among patients attending sexually transmitted disease clinics. We examined whether previous infections or site of infection altered the local and systemic antigonococcal antibody levels in males and females. Antibodies against N. gonorrhoeae MS11 and the patients’ homologous infecting isolates were measured by enzyme-linked immunosorbent assay. In general, the local and systemic immune responses to gonococci were extremely modest. There was a slight increase in serum immunoglobulin G (IgG) against the MS11 strain and the homologous isolates in infected males. Levels of serum IgA1 antibodies against MS11 were slightly higher in infected than in uninfected females. A history of previous infections with N. gonorrhoeae did not alter the antibody levels in patients with a current infection, suggesting that immunological memory is not induced by uncomplicated gonococcal infections. Antibody responses to infected subjects’ homologous isolates were observed in cervical mucus; IgA1 levels increased while IgG levels decreased. The decline in mucosal IgG against the homologous isolates was less common in subjects having both rectal and cervical infections; otherwise, no effect of rectal involvement was observed. The absence of substantially higher antibody levels to gonococci where there is infection at a site known to contain organized lymphoid tissue suggests that the low levels of responses to uncomplicated infections may not be due simply to an absence of inductive sites in the genital tract. We propose that in addition to its potential ability to avoid the effects of an immune response,N. gonorrhoeae does not elicit strong humoral immune responses during uncomplicated genital infections.

scholarly journals Plasmodium falciparumMSP3 Exists in a Complex on the Merozoite Surface and Generates Antibody Response during Natural Infection

2018 ◽  
Vol 86 (8) ◽  
Author(s):  
Arunaditya Deshmukh ◽  
Bishwanath Kumar Chourasia ◽  
Sonali Mehrotra ◽  
Ikhlaq Hussain Kana ◽  
Gourab Paul ◽  
...  
Keyword(s):  
Malaria Vaccine ◽  
Transmembrane Domain ◽  
Natural Infection ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Mass Spectrometry Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
T Cell Epitopes ◽  
Hyperimmune Serum ◽  
Content Type

ABSTRACTPlasmodium falciparummerozoite surface protein 3 (MSP3) is an abundantly expressed secreted merozoite surface protein and a leading malaria vaccine candidate antigen. However, it is unclear how MSP3 is retained on the surface of merozoites without a glycosylphosphatidylinositol (GPI) anchor or a transmembrane domain. In the present study, we identified an MSP3-associated network on thePlasmodiummerozoite surface by immunoprecipitation ofPlasmodiummerozoite lysate using antibody to the N terminus of MSP3 (anti-MSP3N) followed by mass spectrometry analysis. The results suggested the association of MSP3 with other merozoite surface proteins: MSP1, MSP6, MSP7, RAP2, and SERA5. Protein-protein interaction studies by enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) analysis showed that MSP3 complex consists of MSP1, MSP6, and MSP7 proteins. Immunological characterization of MSP3 revealed that MSP3N is strongly recognized by hyperimmune serum from African and Asian populations. Furthermore, we demonstrate that human antibodies, affinity purified against recombinant MSP3N (rMSP3N), promote opsonic phagocytosis of merozoites in cooperation with monocytes. At nonphysiological concentrations, anti-MSP3N antibodies inhibited the growth ofP. falciparum in vitro. Together, the data suggest that MSP3 and especially its N-terminal region containing known B/T cell epitopes are targets of naturally acquired immunity against malaria and also comprise an important candidate for a multisubunit malaria vaccine.

scholarly journals Assessment of Antibody Response Elicited by a 7-valent Pneumococcal Conjugate Vaccine in Pediatric Human Immunodeficiency Virus Infection

2005 ◽  
Vol 12 (1) ◽  
pp. 165-170 ◽  
Author(s):  
David Tarragó ◽  
Julio Casal ◽  
Jesús Ruiz-Contreras ◽  
J. Tomás Ramos ◽  
Pablo Rojo ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Immune Responses ◽  
Conjugate Vaccine ◽  
Pneumococcal Conjugate Vaccine ◽  
Correlation Coefficients ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunodeficiency Virus ◽  
Vaccine Immunogenicity ◽  
Functional Antibodies

ABSTRACT We investigated antibody responses against pneumococci of serotypes 6B, 14, and 23F in 56 children and adolescents with perinatal human immunodeficiency virus (HIV) infection who were vaccinated with 7-valent pneumococcal conjugate vaccine. Overall immune responses differed greatly between serotypes. Correlation coefficients between immunoglobulin G (IgG) measured by enzyme-linked immunosorbent assay (ELISA) and functional antibodies measured by a flow cytometry opsonophagocytosis assay (OPA) varied with serotype and time points studied. After 3 months of administering a second PCV7 dose we got the highest correlation (with significant r values of 0.754, 0.414, and 0.593 for serotypes 6B, 14, and 23F, respectively) but no significant increase in IgG concentration and OPA titers compared to the first dose. We defined a responder to a serotype included in the vaccine with two criteria: frequency of at least twofold OPA and ELISA increases for each serotype and frequency of conversion from negative to positive OPA levels. Responders varied from 43.9% to 46.3%, 28.5% to 50.0%, and 38.0% to 50.0% for serotypes 6B, 14, and 23F, respectively, depending on the response criterion. The present research highlights the importance of demonstrating vaccine immunogenicity with suitable immunological endpoints in immunocompromised patients and also the need to define how much antibody is required for protection from different serotypes, since immunogenicity differed significantly between serotypes.

scholarly journals Antibodies to Borrelia burgdorferi OspA, OspC, OspF, and C6 Antigens as Markers for Early and Late Infection in Dogs

2012 ◽  
Vol 19 (4) ◽  
pp. 527-535 ◽  
Author(s):  
Bettina Wagner ◽  
Heather Freer ◽  
Alicia Rollins ◽  
David Garcia-Tapia ◽  
Hollis N. Erb ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
The United States ◽  
Sensu Stricto ◽  
Antibody Responses ◽  
Surface Proteins ◽  
Early Infection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Content Type ◽  
Antibody Levels

ABSTRACTLyme disease in the United States is caused byBorrelia burgdorferisensu stricto, which is transmitted to mammals by infected ticks.Borreliaspirochetes differentially express immunogenic outer surface proteins (Osp). Our aim was to evaluate antibody responses to Osp antigens to aid the diagnosis of early infection and the management of Lyme disease. We analyzed antibody responses during the first 3 months after the experimental infection of dogs using a novel multiplex assay. Results were compared to those obtained with two commercial assays detecting C6 antigen. Multiplex analysis identified antibodies to OspC and C6 as early as 3 weeks postinfection (p.i.) and those to OspF by 5 weeks p.i. Antibodies to C6 and OspF increased throughout the study, while antibodies to OspC peaked between 7 and 11 weeks p.i. and declined thereafter. A short-term antibody response to OspA was observed in 3/8 experimentally infected dogs on day 21 p.i. Quant C6 enzyme-linked immunosorbent assay (ELISA) results matched multiplex results during the first 7 weeks p.i.; however, antibody levels subsequently declined by up to 29%. Immune responses then were analyzed in sera from 125 client-owned dogs and revealed high agreement between antibodies to OspF and C6 as robust markers for infection. Results from canine patient sera supported that OspC is an early infection marker and antibodies to OspC decline over time. The onset and decline of antibody responses toB. burgdorferiOsp antigens and C6 reflect their differential expression during infection. They provide valuable tools to determine the stage of infection, treatment outcomes, and vaccination status in dogs.

scholarly journals Safety and Immunogenicity of a Recombinant Nonglycosylated Erythrocyte Binding Antigen 175 Region II Malaria Vaccine in Healthy Adults Living in an Area Where Malaria Is Not Endemic

2010 ◽  
Vol 17 (10) ◽  
pp. 1552-1559 ◽  
Author(s):  
H. M. El Sahly ◽  
S. M. Patel ◽  
R. L. Atmar ◽  
T. A. Lanford ◽  
T. Dube ◽  
...  
Keyword(s):  
United States ◽  
Malaria Vaccine ◽  
Aluminum Phosphate ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Systemic Reactions ◽  
Erythrocyte Binding ◽  
Low Levels ◽  
Antibody Levels ◽  
Region Ii

ABSTRACT Erythrocyte binding antigen region II (EBA-175) is a conserved antigen of Plasmodium falciparum that is involved in binding of the parasite to the host's erythrocytes. We evaluated the safety and immunogenicity of a recombinant EBA-175 vaccine with aluminum phosphate adjuvant in healthy young adults living in the United States. Eighteen subjects/group received ascending doses (5, 20, 80, or 160 μg) of the vaccine at 0, 1, and 6 months; 8 subjects received placebo. Most of the injection site and systemic reactions were mild to moderate in intensity. After 2 or 3 doses of the vaccine at any concentration, antibody levels measured by enzyme-linked immunosorbent assay were significantly higher than those for the placebo group. Sera from subjects who received 3 doses of the vaccine at any concentration inhibited the growth of erythrocyte-stage P. falciparum at low levels compared to sera from placebo recipients or preimmune sera. In conclusion, the EBA-175 vaccine with adjuvant was safe and immunogenic in malaria-naïve subjects.

scholarly journals Long-Term Course of Humoral and Cellular Immune Responses in Outpatients After SARS-CoV-2 Infection

2021 ◽  
Vol 9 ◽  
Author(s):  
Julia Schiffner ◽  
Insa Backhaus ◽  
Jens Rimmele ◽  
Sören Schulz ◽  
Till Möhlenkamp ◽  
...  
Keyword(s):  
Immune Responses ◽  
Peripheral Blood ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Disease Course ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Moderate Disease ◽  
Ifn Γ ◽  
Antibody Levels

Characterization of the naturally acquired B and T cell immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important for the development of public health and vaccination strategies to manage the burden of COVID-19 disease. We conducted a prospective, cross-sectional analysis in COVID-19 recovered patients at various time points over a 10-month period in order to investigate how circulating antibody levels and interferon-gamma (IFN-γ) release by peripheral blood cells change over time following natural infection. From March 2020 till January 2021, we enrolled 412 adults mostly with mild or moderate disease course. At each study visit, subjects donated peripheral blood for testing of anti-SARS-CoV-2 IgG antibodies and IFN-γ release after SARS-CoV-2 S-protein stimulation. Anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies were positive in 316 of 412 (76.7%) and borderline in 31 of 412 (7.5%) patients. Our confirmation assay for the presence of neutralizing antibodies was positive in 215 of 412 (52.2%) and borderline in 88 of 412 (21.4%) patients. Likewise, in 274 of 412 (66.5%) positive IFN-γ release and IgG antibodies were detected. With respect to time after infection, both IgG antibody levels and IFN-γ concentrations decreased by about half within 300 days. Statistically, production of IgG and IFN-γ were closely associated, but on an individual basis, we observed patients with high-antibody titres but low IFN-γ levels and vice versa. Our data suggest that immunological reaction is acquired in most individuals after natural infection with SARS-CoV-2 and is sustained in the majority of patients for at least 10 months after infection after a mild or moderate disease course. Since, so far, no robust marker for protection against COVID-19 exists, we recommend utilizing both, IgG and IFN-γ release for an individual assessment of the immunity status.

scholarly journals Differential Immunogenicity of BNT162b2 or ChAdOx1 Vaccines After Extended-Interval Homologous Dual Vaccination in Older People

2021 ◽  
Author(s):  
Helen Parry ◽  
Rachel Bruton ◽  
Christine Stephens ◽  
Kevin Brown ◽  
Gayatri Amirthalingam ◽  
...  
Keyword(s):  
Immune Responses ◽  
Older People ◽  
Natural Infection ◽  
Cellular Responses ◽  
Antibody Responses ◽  
Vaccine Responses ◽  
Cell Responses ◽  
Boost Vaccine ◽  
The Uk ◽  
Cellular Immune

Abstract BackgroundSeveral SARS-CoV-2 vaccines have shown clinical efficacy against Covid-19 infection but there remains uncertainty about the immune responses elicited by different regimens. This is a particularly important question for older people who are at increased clinical risk following infection and in whom immune senescence may limit vaccine responses. The BNT162b2 mRNA and ChAdOx1 adenovirus vaccines were the first two vaccines deployed in the UK programme using an 8-12 week ‘extended interval’.ObjectivesWe undertook analysis of the spike-specific antibody and cellular immune response in 131 participants aged 80+ years after the second dose of ‘extended interval’ dual vaccination with either BNT162b2 mRNA (n=54) or ChAdOx1 (n=77) adenovirus vaccine. Blood samples were taken 2-3 weeks after second vaccine and were paired with samples taken at 5-weeks after first vaccine which have been reported previously. Antibody responses were measured using the Elecsys® electrochemiluminescence immunoassay assay and cellular responses were assessed by IFN-g ELISpot. ResultsAntibody responses against spike protein became detectable in all donors following dual vaccination with either vaccine. 4 donors had evidence of previous natural infection which is known to boost vaccine responses. Within the 53 infection-naïve donors the median antibody titre was 4030 U/ml (IQR 1892-8530) following BNT162b2 dual vaccination and 1405 (IQR 469.5- 2543) in the 74 patients after the ChAdOx1 vaccine (p=<0.0001). Spike-specific T cell responses were observed in 30% and 49% of mRNA and ChAdOx1 recipients respectively and median responses were 1.4-times higher in ChAdOx1 vaccinees at 14 vs 20 spots/million respectively (p=0.022).ConclusionDual vaccination with BNT162b2 or ChAdOx1 induces strong humoral immunity in older people following an extended interval protocol. Antibody responses are 2.9-times higher following the mRNA regimen whilst cellular responses are 1.7-times higher with the adenovirus-based vaccine. Differential patterns of immunogenicity are therefore elicited from the two vaccine platforms. It will be of interest to assess the relative stability of immune responses after these homologous vaccine regimens in order to assess the potential need for vaccine boosting. Furthermore, these findings indicate that heterologous vaccine platforms may offer the opportunity to further optimize vaccine responses.

scholarly journals A "Made-in-Canada" serology solution for profiling humoral immune responses to SARS-CoV-2 infection and vaccination

2021 ◽  
Author(s):  
Karen Colwill ◽  
Yannick Galipeau ◽  
Matthew Stuible ◽  
Christian Gervais ◽  
Corey Arnold ◽  
...  
Keyword(s):  
Immune Responses ◽  
High Throughput ◽  
Natural Infection ◽  
National Research Council ◽  
World Health ◽  
Enzyme Linked Immunosorbent Assay ◽  
Functional Assay ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Made In

BACKGROUND: Testing for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been instrumental in detecting previous exposures and analyzing vaccine-elicited immune responses. Here, we describe a scalable "Made-in-Canada" solution that can detect and quantify SARS-CoV-2 antibodies, discriminate between natural infection- and vaccination-induced responses, and assess antibody-mediated inhibition of the spike-angiotensin converting enzyme 2 (ACE2) interaction. METHODS: We developed a set of methods and reagents to detect SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA). The main assays focus on the parallel detection of immunoglobulin (Ig)Gs against the spike trimer, its receptor binding domain (RBD), and the nucleocapsid (N) protein. These antigens are complemented by a detection antibody (human anti-IgG fused to horseradish peroxidase (HRP)) and a positive control reference antibody (recombinant IgG against the RBD), permitting intra- and inter-laboratory comparisons. Using this toolkit and commercial reagents, we optimized automated ELISAs on two different high throughput platforms to measure antibody responses to SARS-CoV-2 antigens. The assays were calibrated to a reference standard from the World Health Organization. We also automated a surrogate neutralization (sn)ELISA that measures inhibition of ACE2-Spike or -RBD interactions by antibodies using biotinylated ACE2. RESULTS: Our individual IgG-based ELISAs measure antibody levels in single-point measurements in reference to a standard antibody curve to accurately distinguish non-infected and infected individuals (area under the curve > 0.96 for each assay). Positivity thresholds can be established in individual assays using precision-recall analysis (e.g., by fixing the false positive rate), or more stringently, by scoring against the distribution of the means of negative samples across multiple assays performed over several months. For seroprevalence assessment (in a non-vaccinated cohort), classifying a sample as positive if antibodies were detected for at least 2 of the 3 antigens provided the highest specificity. In vaccinated cohorts, increases in anti-spike and -RBD (but not -N) antibodies are observed. Here, we present detailed protocols to perform these assays using either serum/plasma or dried blood spots both manually and on two automated platforms, and to express the results in international units to facilitate data harmonization and inter-study comparisons. We also demonstrate that the snELISA can be performed automatically at single points, increasing the scalability of this functional assay for large seroprevalence studies. INTERPRETATION: The ability to measure antibodies to three viral antigens and identify neutralizing antibodies capable of disrupting spike-ACE2 interactions in high-throughput assays enables large-scale analyses of humoral immune responses to SARS-CoV-2 infection and vaccination. The "Made-in-Canada" set of protein reagents, produced at the National Research Council of Canada are publicly available to enable the up-scaling of standardized serological assays, permitting nationwide data comparison and aggregation.

scholarly journals 411. Application of a SARS-CoV-2-specific serologic assay for translational research and surveillance

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S273-S273
Author(s):  
Amy C Sherman ◽  
Teresa C Smith ◽  
Daniel Espinoza ◽  
Yerun Zhu ◽  
Jessica Howard-Anderson ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Roc Curve ◽  
Research Training ◽  
Natural Infection ◽  
Curve Analysis ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Research Support ◽  
Roc Curve Analysis

Abstract Background Sensitive and specific SARS-CoV-2 antibody diagnostics are urgently needed to estimate the seroprevalence of SARS-CoV-2 infection in both the general population and special risk groups. Moreover, validated serologic assays are critical to understanding immunity to SARS-CoV-2 infection over time and identifying correlates of protection. Methods An enzyme-linked immunosorbent assay (ELISA) protocol to detect antibodies (IgG) that bind the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein was validated and ROC curve analysis performed by testing a large panel of pre-pandemic sera (n=162) and convalescent sera from RT-PCR-confirmed COVID-19 cases (n=60). We then applied this test in two cohorts: 1) Healthcare personnel (HCP) that were enrolled in a longitudinal surveillance cohort just after peak local transmission and 2) Mildly ill patients being tested for SARS-CoV-2 infection by RT-PCR from NP swabs in an ambulatory testing clinic. Demographics of mildly symptomatic patients tested for SARS-CoV-2 with RT-PCR Results ROC curve analysis yielded an AUC of 0.9953, with a sensitivity and specificity at 91.67% and 99.38% at the optimal OD normalization threshold of 0.20. In 240 HCP surveilled at enrollment, 5.83% had positive IgG results. Of 19 symptomatic patients who presented to the ambulatory clinic, 5/19 had a positive PCR. In convalescence (13–74 days post symptom onset), 3 of those 5 were positive for IgG. Validation of the SARS-CoV-2 RBD ELISA ROC Curve Analysis Conclusion We demonstrated high sensitivity and specificity of the SARS-CoV-2 RBD ELISA. This simple assay is an efficient way to track seroconversion and duration of antibody responses to SARS-CoV-2 for different populations, particularly since RBD-binding antibodies have been shown to correlate with neutralization activity and may be useful to determine protective immunity following natural infection or vaccination. Ongoing work will assess variation in magnitude, character and duration of antibody responses in key populations and seek to maximize deployability of large-scale SARS-CoV-2 serology. Disclosures Jessica Howard-Anderson, MD, MSc, Antibacterial Resistance Leadership Group (ARLG) (Other Financial or Material Support, The ARLG fellowship provides salary support for ID fellowship and mentored research training) Nadine Rouphael, MD, Lilly (Grant/Research Support)Merck (Grant/Research Support)Pfizer (Grant/Research Support)Quidel (Grant/Research Support)Sanofi Pasteur (Grant/Research Support)

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