scholarly journals A high content microscopy-based platform for detecting antibodies to the nucleocapsid, spike and membrane proteins of SARS-CoV-2

Author(s):  
Daniel M. Williams ◽  
Hayley Hornsby ◽  
Ola M. Shehata ◽  
Rebecca Brown ◽  
Domen Zafred ◽  
...  

The strong humoral immune response produced against the SARS-CoV-2 nucleocapsid (N) and spike (S) proteins has underpinned serological testing but the prevalence of antibody responses to other SARS-CoV-2 proteins, which may be of use as further serological markers, is still unclear. Cell-based serological screening platforms can fulfil a crucial niche in the identification of antibodies which recognise more complex folded epitopes or those incorporating post-translation modifications which may be undetectable by other methods used to investigate the antigenicity of the SARS-CoV-2 proteome. Here, we employed automated high content immunofluorescence microscopy (AHCIM) to assess the viability of such an approach as a method capable of assaying humoral immune responses against full length SARS-CoV-2 proteins in their native cellular state. We first demonstrate that AHCIM provides high sensitivity and specificity in the detection of SARS-CoV-2 N and S IgG. Assessing the prevalence of antibody responses to the SARS-CoV-2 structural membrane protein (M), we further find that 85% of COVID-19 patients within our sample set developed detectable M IgG responses (M sensitivity 85%, N sensitivity 93%, combined N + M sensitivity 95%). The identification of M as a serological marker of high prevalence may be of value in detecting additional COVID-19 cases during the era of mass SARS-CoV-2 vaccinations, where serological screening for SARS CoV-2 infections in vaccinated individuals is dependent on detection of antibodies against N. These findings highlight the advantages of using cell-based systems as serological screening platforms and raise the possibility of using M as a widespread serological marker alongside N and S.

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Helen Parry ◽  
Gokhan Tut ◽  
Rachel Bruton ◽  
Sian Faustini ◽  
Christine Stephens ◽  
...  

Age is the major risk factor for mortality after SARS-CoV-2 infection and older people have received priority consideration for COVID-19 vaccination. However, vaccine responses are often suboptimal in this age group and few people over the age of 80 years were included in vaccine registration trials. We determined the serological and cellular response to spike protein in 100 people aged 80–96 years at 2 weeks after the second vaccination with the Pfizer BNT162b2 mRNA vaccine. Antibody responses were seen in every donor with high titers in 98%. Spike-specific cellular immune responses were detectable in only 63% and correlated with humoral response. Previous SARS-CoV-2 infection substantially increased antibody responses after one vaccine and antibody and cellular responses remained 28-fold and 3-fold higher, respectively, after dual vaccination. Post-vaccine sera mediated strong neutralization of live Victoria infection and although neutralization titers were reduced 14-fold against the P.1 variant first discovered in Brazil they remained largely effective. These data demonstrate that the mRNA vaccine platform delivers strong humoral immunity in people up to 96 years of age and retains broad efficacy against the P.1 variant of concern.


1999 ◽  
Vol 67 (8) ◽  
pp. 3937-3946 ◽  
Author(s):  
Spencer R. Hedges ◽  
Matthew S. Mayo ◽  
Jiri Mestecky ◽  
Edward W. Hook ◽  
Michael W. Russell

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.


1981 ◽  
Vol 98 (4) ◽  
pp. 506-513 ◽  
Author(s):  
Istvan Berczi ◽  
Eva Nagy ◽  
Kalman Kovacs ◽  
Eva Horvath

Abstract. Hypophysectomized female Fischer 344 and Wistar-Furth rats had severely impaired primary and secondary antibody responses to sheep red blood cells (SRBC). Mercaptoethanol-sensitive (IgM) and mercaptoethanol-resistant (IgG) antibodies were similarly affected. Titers to E. Coli 055:B5 lipopolysaccharide were also significantly decreased in such animals. The antibody response of hypophysectomized rats could be restored by syngeneic pituitary grafts when placed under the kidney capsule or by prolactin treatment. Growth hormone was less effective in this respect than prolactin. Treatment of normal rats with ACTH suppressed their antibody formation to SRBC. These results indicate that the pituitary gland has the potential to regulate humoral immune responses.


2001 ◽  
Vol 69 (12) ◽  
pp. 7437-7444 ◽  
Author(s):  
Austin Vaz ◽  
Lisa Glickstein ◽  
Jodie A. Field ◽  
Gail McHugh ◽  
Vijay K. Sikand ◽  
...  

ABSTRACT We determined cellular and humoral immune responses toBorrelia burgdorferi lysate and to recombinant flagellin (FlaB), OspC, and OspA in acute- and convalescent-phase samples from 39 culture-positive patients with erythema migrans and in 20 healthy control subjects. During the acute illness, a median of 4 days after the onset of erythema migrans, 51% of the patients had proliferative cellular responses and 72% had antibody responses to at least one of the borrelial antigens tested. During convalescence, at the conclusion of antibiotic therapy, 64% of the patients had proliferative cellular reactivity and 95% had antibody reactivity with at least one of the spirochetal antigens tested. In both acute- and convalescent-phase samples, cellular immune responses were found as frequently to OspA as to OspC and FlaB. Although antibody responses were also frequently seen to OspC and FlaB, only a few patients had marginal antibody reactivity with OspA. The percentage of patients with proliferative responses was similar in those with clinical evidence of localized or disseminated infection, whereas humoral reactivity was found more often in those with disseminated disease. We conclude that cellular and humoral responses to B. burgdorferi antigens are often found among patients with early Lyme disease. In contrast with the other antigens tested, cellular but not humoral reactivity was often found with OspA.


2006 ◽  
Vol 203 (3) ◽  
pp. 599-606 ◽  
Author(s):  
Silvia B. Boscardin ◽  
Julius C.R. Hafalla ◽  
Revati F. Masilamani ◽  
Alice O. Kamphorst ◽  
Henry A. Zebroski ◽  
...  

Resistance to several prevalent infectious diseases requires both cellular and humoral immune responses. T cell immunity is initiated by mature dendritic cells (DCs) in lymphoid organs, whereas humoral responses to most antigens require further collaboration between primed, antigen-specific helper T cells and naive or memory B cells. To determine whether antigens delivered to DCs in lymphoid organs induce T cell help for antibody responses, we targeted a carrier protein, ovalbumin (OVA), to DCs in the presence of a maturation stimulus and assayed for antibodies to a hapten, (4-hydroxy-3-nitrophenyl) acetyl (NP), after boosting with OVA-NP. A single DC-targeted immunization elicited long-lived T cell helper responses to the carrier protein, leading to large numbers of antibody-secreting cells and high titers of high-affinity antihapten immunoglobulin Gs. Small doses of DC-targeted OVA induced higher titers and a broader spectrum of anti-NP antibody isotypes than large doses of OVA in alum adjuvant. Similar results were obtained when the circumsporozoite protein of Plasmodium yoelii was delivered to DCs. We conclude that antigen targeting to DCs combined with a maturation stimulus produces broad-based and long-lived T cell help for humoral immune responses.


2021 ◽  
Author(s):  
Carolina Garrido ◽  
Jillian H Hurst ◽  
Cynthia G. Lorang ◽  
Jhoanna N. Aquino ◽  
Javier Rodriguez ◽  
...  

As SARS-CoV-2 continues to spread globally, questions have emerged regarding the strength and durability of immune responses in specific populations. In this study, we evaluated humoral immune responses in 69 children and adolescents with asymptomatic or mild symptomatic SARS-CoV-2 infection. We detected robust IgM, IgG, and IgA antibody responses to a broad array of SARS-CoV-2 antigens at the time of acute infection and 2 and 4 months after acute infection in all participants. Notably, these antibody responses were associated with virus neutralizing activity that was still detectable 4 months after acute infection in 94% of children. Moreover, antibody responses and neutralizing activity in sera from children and adolescents were comparable or superior to those observed in sera from 24 adults with mild symptomatic infection. Taken together, these findings indicate children and adolescents with mild or asymptomatic SARS-CoV-2 infection generate robust and durable humoral immune responses that are likely to protect from reinfection.


2021 ◽  
Vol 7 (6) ◽  
pp. eabe5819
Author(s):  
Martin P. Steinbuck ◽  
Lochana M. Seenappa ◽  
Aniela Jakubowski ◽  
Lisa K. McNeil ◽  
Christopher M. Haqq ◽  
...  

The profound consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mandate urgent development of effective vaccines. Here, we evaluated an Amphiphile (AMP) vaccine adjuvant, AMP-CpG, composed of diacyl lipid–modified CpG, admixed with the SARS-CoV-2 Spike-2 receptor binding domain protein as a candidate vaccine (ELI-005) in mice. AMP modification efficiently delivers CpG to lymph nodes, where innate and adaptive immune responses are generated. Compared to alum, immunization with AMP-CpG induced >25-fold higher antigen-specific T cells that produced multiple T helper 1 (TH1) cytokines and trafficked into lung parenchyma. Antibody responses favored TH1 isotypes (IgG2c and IgG3) and potently neutralized Spike-2-ACE2 receptor binding, with titers 265-fold higher than natural convalescent patient COVID-19 responses; T cell and antibody responses were maintained despite 10-fold dose reduction in Spike antigen. Both cellular and humoral immune responses were preserved in aged mice. These advantages merit clinical translation to SARS-CoV-2 and other protein subunit vaccines.


2021 ◽  
Author(s):  
Mark A. Brockman ◽  
Francis M. Mwimanzi ◽  
Hope R. Lapointe ◽  
Yurou Sang ◽  
Olga Agafitei ◽  
...  

Background mRNA vaccines reduce COVID-19 incidence and severity, but the durability of vaccine-induced immune responses, particularly among the elderly, remains incompletely characterized. Methods Anti-spike RBD antibody titers, ACE2 competition and virus neutralizing activities were longitudinally assessed in 151 healthcare workers and older adults (overall aged 24-98 years) up to three months after vaccination. Results Older adults exhibited lower antibody responses after one and two vaccine doses for all measures. In multivariable analyses correcting for sociodemographic, chronic health and vaccine-related variables, age remained independently associated with all response outcomes. The number of chronic health conditions was additionally associated with lower binding antibody responses after two doses, and male sex with lower ACE2 competition activity after one dose. Responses waned universally at three months after the second dose, but binding antibodies, ACE2 competition and neutralizing activities remained significantly lower with age. Older adults also displayed reduced ability to block ACE2 binding by the Delta variant. Conclusions The humoral immune response to COVID-19 mRNA vaccines is significantly weaker with age, and universally wanes over time. This will likely reduce antibody-mediated protection against SARS-CoV-2 and the Delta variant as the pandemic progresses. Older adults may benefit from additional immunizations as a priority.


Blood ◽  
1998 ◽  
Vol 92 (4) ◽  
pp. 1324-1333 ◽  
Author(s):  
Debra A. Cockayne ◽  
Tony Muchamuel ◽  
J. Christopher Grimaldi ◽  
Hélène Muller-Steffner ◽  
Troy D. Randall ◽  
...  

Abstract CD38 is a membrane-associated ecto-nicotinamide adenine dinucleotide (NAD+) glycohydrolase that is expressed on multiple hematopoietic cells. The extracellular domain of CD38 can mediate the catalysis of NAD+ to cyclic adenosine diphosphoribose (cADPR), a Ca2+-mobilizing second messenger, adenosine diphosphoribose (ADPR), and nicotinamide. In addition to its enzymatic properties, murine CD38 has been shown to act as a B-cell coreceptor capable of modulating signals through the B-cell antigen receptor. To investigate the in vivo physiological function(s) of this novel class of ectoenzyme we generated mice carrying a null mutation in the CD38 gene. CD38−/− mice showed a complete loss of tissue-associated NAD+ glycohydrolase activity, showing that the classical NAD+ glycohydrolases and CD38 are likely identical. Although murine CD38 is expressed on hematopoietic stem cells as well as on committed progenitors, we show that CD38 is not required for hematopoiesis or lymphopoiesis. However, CD38−/− mice did exhibit marked deficiencies in antibody responses to T-cell–dependent protein antigens and augmented antibody responses to at least one T-cell–independent type 2 polysaccharide antigen. These data suggest that CD38 may play an important role in vivo in regulating humoral immune responses. © 1998 by The American Society of Hematology.


Parasitology ◽  
1987 ◽  
Vol 95 (3) ◽  
pp. 559-568 ◽  
Author(s):  
N. M. Almond ◽  
M. J. Worms ◽  
W. Harnett ◽  
R. M. E. Parkhouse

SUMMARYThe class-specific antibody responses of 3 strains of mice (C57/Bl10, BALB/C and CBA/N) known to vary in their ability to control the microfilaraemia which follows the subcutaneous transplantation of adult femaleDipetalonema viteaehas been investigated. The 3 mouse strains showed significant variation (a) in total levels of immunoglobulins and (b) in ability to recognize individual radio-isotope-labelled antigens as measured by coprecipitation. Within each mouse strain it was noted that antigens could vary with respect to the nature of the isotype of the antibody response which they elicited. Furthermore, by comparing results obtained from class-specific coprecipitation with surface ELISA it was found that a similar variation between responses to individual epitopes was also likely. No differences were observed in the humoral response of the 3 mouse strains which could explain the known resistance of the C57/B110 strain; reasons for this are discussed.


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