Longitudinal Analysis of Virus Load, Serum Antibody Levels and Virus Neutralizing Activity In Vitro in Cases with Less Severe COVID-19

Background: Patients infected with SARS-CoV-2 exhibit a highly variable clinical course, varying from barely discernible signs of disease, to moderate flu-like symptoms and, occasionally, with life-threatening pneumonia and/or cytokine storm. The relationship between the nasopharyngeal virus load, IgA and IgG antibodies to both the S1-RBD-protein and the N-protein as well the neutralizing activity (NAbs) against SARS-CoV-2 in the blood of moderately afflicted COVID-19 patients has not been investigated longitudinally so far. Methods: Several new serological methods to examine these parameters were developed and validated for the longitudinal investigation in three patients of a family which underwent a mild course of COVID-19. Findings: We observed that the virus load had almost completely disappeared after about four weeks, whereas serum antibodies showed a contrasting course. IgA levels to S1-RBD-protein and, to a lesser extent, to the N-protein, peaked about three weeks after clinical disease onset but declined soon thereafter. IgG levels rose continuously, reaching a plateau approximately six weeks after disease onset. NAbs in serum reached a peak about four weeks after disease onset but dropped to a lower level about six weeks later. Interpretation: Our data establishes associations of virus neutralization and a serological immune response foremost against Sars-CoV-2 S1-RDB-protein in a longitudinal manner.

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Ontogenesis of the formation of secretory antibodies to respiratory syncytial (RS) virus

Epidemiology and Infection ◽

10.1017/s0950268800029435 ◽

1988 ◽

Vol 101 (3) ◽

pp. 565-575 ◽

Cited By ~ 3

Author(s):

N. P Leschinskaya ◽

E. E Pokrovskaya ◽

E. A Kantorovitch ◽

S.K Grigorjeva ◽

YA. S Shvartsman

Keyword(s):

Old Age ◽

Serum Antibody ◽

Close Correlation ◽

Secretory Iga ◽

Igg Antibodies ◽

Virus Infections ◽

Neutralizing Activity ◽

Iga Antibodies ◽

Antibody Levels ◽

Secretory Antibodies

SUMMARYExamination of sera from 184 children aged between 0 and 12 years and 161 adults revealed a close correlation between age and the level of humoral anti-RS virus immunity. Secretory IgG antibodies were found in children in their first months of life. Evidence for their release into secretions from the serum was obtained. This might explain the positive correlation between serum antibody levels in women recently confined with the morbidity due to RS virus in children during their first months of life. Secretory IgA antibodies were found from 4 months untill old age. The secretions of children and adults contained virus-neutralizing activity which was non-immunoglobulin in nature, as well as antibodies. However, in contrast to secretory antibody this material did not prevent development of severe RS virus infections.

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Identification and characterization of a putative agglutination/immobilization antigen on the surface ofCryptocaryon irritans

Parasitology ◽

10.1017/s003118200700265x ◽

2007 ◽

Vol 134 (9) ◽

pp. 1163-1174 ◽

Cited By ~ 22

Author(s):

A. HATANAKA ◽

N. UMEDA ◽

S. YAMASHITA ◽

N. HIRAZAWA

Keyword(s):

Serum Antibody ◽

Integral Membrane Protein ◽

Control Fish ◽

Booster Immunization ◽

Immobilization Antigen ◽

Indirect Immunofluorescence Staining ◽

Tiger Puffer ◽

Biochemical Analyses ◽

Antibody Levels

SUMMARYThe ciliated protozoanCryptocaryon irritans, a parasite of seawater fishes, was found to express an antigen that elicits antibodies in rabbits and tiger puffer (Takifugu ruburipes). Serum from rabbits and fish immunized with theronts had agglutination/immobilization activity against therontsin vitro; fish serum antibody levels (measured by enzyme-linked immunosorbent assays: ELISA) correlated with this activity. Anti-theront antibody levels in fish were significantly higher in the immunized group as compared with control fish at 2 weeks after booster immunization (injection of bovine serum albumin; Student'st-test,P<0·01). Biochemical analyses indicated that a Triton X-114-soluble 32 kDa theront integral membrane protein may be the agglutination/immobilization antigen. Indirect immunofluorescence staining of theronts suggested that this 32 kDa antigen was expressed on the surface of cilia. The full-length 32 kDa antigen cDNA contained 1147 basepairs, encoding a 328-amino acid protein including hydrophobic N- and C-termini. As withTetrahymenaandParameciumspp., TAA and TAG appear to be used as glutamine codons in the 32 kDa antigen gene.

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Lack of Humoral Immune Protection againstTreponema denticola Virulence in a Murine Model

Infection and Immunity ◽

10.1128/iai.67.11.5736-5746.1999 ◽

1999 ◽

Vol 67 (11) ◽

pp. 5736-5746 ◽

Cited By ~ 13

Author(s):

Lakshmyya Kesavalu ◽

Stanley C. Holt ◽

Jeffrey L. Ebersole

Keyword(s):

Immune Responses ◽

Primary Infection ◽

Serum Antibody ◽

Active Immunization ◽

Antigenic Specificity ◽

Immune Protection ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Antibody Levels

ABSTRACT This study investigated the characteristics of humoral immune responses to Treponema denticola following primary infection, reinfection, and active immunization, as well as immune protection in mice. Primary infection with T. denticolainduced a significant (400-fold) serum immunoglobulin G (IgG) response compared to that in control uninfected mice. The IgG response to reinfection was 20,000-fold higher than that for control mice and 10-fold higher than that for primary infection. Mice actively immunized with formalin-killed treponemes developed serum antibody levels seven- to eightfold greater than those in animals after primary infection. Nevertheless, mice with this acquired antibody following primary infection or active immunization demonstrated no significant alterations of lesion induction or decreased size of the abscesses following a challenge infection. Mice with primary infection developed increased levels of IgG3, IgG2b, and IgG2a antibodies, with IgG1 being lower than the other subclasses. Reinfected mice developed enhanced IgG2b, IgG2a, and IgG3 and less IgG1. In contrast, immunized mice developed higher IgG1 and lower IgG3 antibody responses to infection. These IgG subclass distributions indicate a stimulation of both Th1 and Th2 activities in development of the humoral immune response to infection and immunization. Our findings also demonstrated a broad antigen reactivity of the serum antibody, which was significantly increased with reinfection and active immunization. Furthermore, serum antibody was effective in vitro in immobilizing and clumping the bacteria but did not inhibit growth or passively prevent the treponemal infection. These observations suggest that humoral immune responses, as manifested by antibody levels, isotype, and antigenic specificity, were not capable of resolving a T. denticola infection.

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Coimmunization with Complementary Glucosyltransferase Peptides Results in Enhanced Immunogenicity and Protection against Dental Caries

Infection and Immunity ◽

10.1128/iai.68.5.2698-2703.2000 ◽

2000 ◽

Vol 68 (5) ◽

pp. 2698-2703 ◽

Cited By ~ 20

Author(s):

Martin A. Taubman ◽

Daniel J. Smith ◽

Cynthia J. Holmberg ◽

Jean W. Eastcott

Keyword(s):

Dental Caries ◽

Functional Significance ◽

Serum Antibody ◽

Mutans Streptococci ◽

Streptococcus Sobrinus ◽

Insoluble Glucan ◽

Glucan Synthesis ◽

The Individual ◽

Antibody Levels

ABSTRACT Peptide constructs from the catalytic (CAT) and glucan-binding (GLU) regions of the mutans streptococcal glucosyltransferase enzymes (GTF) can provide immunity to dental caries infection. A strategy of coimmunization was tested to determine whether protection could be enhanced. Rats were immunized with one of the previously described peptide constructs from the CAT or GLU region of the GTF of mutans streptococci or coimmunized with a combination of these constructs (CAT-GLU). Coimmunized animals demonstrated significantly higher serum immunoglobulin G (IgG) and salivary IgA antibody levels to CAT or GTF than rats immunized with either construct alone. To assess the functional significance of coimmunization with these constructs, animals were immunized as above or with Streptococcus sobrinus GTF and then infected with S. sobrinus to explore the effects of immunization on immunological, microbiological, and disease (dental caries) parameters. Serum antibody from the communized group inhibited S. sobrinus GTF-mediated insoluble glucan synthesis in vitro above that of the individual-construct-immunized groups. Immunization with CAT or GLU constructs resulted in significantly reduced dental caries after infection with S. sobrinus compared with sham-immunized animals. Coimmunization produced greater reductions in caries than after immunization with either CAT or GLU. Also, significant elevations in lymphocyte proliferative responses to CAT, GLU, and GTF were observed after coimmunization with CAT-GLU compared with the responses after immunization with the individual constructs. The results suggested that increased numbers of memory T cells, which could proliferate to CAT, were generated by coimmunization. The experiments support the functional significance of these GTF domains in dental caries pathogenesis and present coimmunization as a simple alternative to intact GTF to enhance protective immunity against cariogenic microorganisms.

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Enhanced Murine Antigen-Specific Gamma Interferon and Immunoglobulin G2a Responses by Using Mycobacterial ESAT-6 Sequences in DNA Vaccines

Infection and Immunity ◽

10.1128/iai.71.4.2239-2243.2003 ◽

2003 ◽

Vol 71 (4) ◽

pp. 2239-2243 ◽

Cited By ~ 10

Author(s):

F. Chris Minion ◽

Sreekumar A. Menon ◽

Gregory G. Mahairas ◽

M. J. Wannemuehler

Keyword(s):

Immune Responses ◽

Dna Vaccines ◽

Serum Antibody ◽

Interleukin 10 ◽

Gamma Interferon ◽

Viral Pathogens ◽

Ifn Γ ◽

Antibody Levels

ABSTRACT The Mycobacterium tuberculosis protein ESAT-6 has unusual immune stimulating activities, has been implicated in the recall of long-lived immunity, and induces protection against tuberculosis in mice. For many diseases caused by bacterial or viral pathogens, a strong cell-mediated immune (i.e., type 1) response is often required for recovery or protection. Therefore, it is important to design immunization regimens that induce agent-specific type 1 immunity. We have shown in previous studies that ESAT-6 could enhance antigen-specific type 1 immune responses in BALB/c mice against a second antigen when presented as a purified fusion protein. It was also of interest to determine if ESAT-6 could enhance the type 1 response against a second antigen beyond that afforded by DNA vaccination through CpG motifs. This was tested by using gene fusions of ESAT-6 and the Mycoplasma hyopneumoniae surface antigen P71. Modified P71 gene sequences were cloned with or without ESAT-6 sequences into a DNA vaccine vector and were used to immunize mice. Splenic lymphocytes from vaccinated mice were tested for gamma interferon (IFN-γ) and interleukin-10 (IL-10) secretion. Serum antibodies were examined for P71 antigen-specific isotype responses. When stimulated in vitro with purified P71 antigen, splenocytes from the ESAT-6:P71 vaccinates secreted higher levels of IFN-γ and lower levels of IL-10 compared to those of vaccinates receiving the P71 construct alone. Furthermore, the immunoglobulin G2a serum antibody levels were significantly higher in the ESAT-6:P71 vaccinates compared to those of the vaccinates receiving P71 alone. In conclusion, ESAT-6 was shown to enhance antigen-specific type 1 immune responses in BALB/c mice when used in DNA vaccines.

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Antibody response of carp, Cyprinus carpio to the cestode, Bothriocephalus acheilognathi

Parasitology ◽

10.1017/s0031182099004242 ◽

1999 ◽

Vol 118 (6) ◽

pp. 635-639 ◽

Cited By ~ 11

Author(s):

P. NIE ◽

D. HOOLE

Keyword(s):

Antibody Response ◽

Cyprinus Carpio ◽

Serum Antibody ◽

Infected Fish ◽

Immune Protection ◽

Carp Cyprinus Carpio ◽

Bothriocephalus Acheilognathi ◽

Protection Against Infection ◽

Antibody Levels ◽

Antibody Secreting Cells

The humoral antibody response and the number of pronephric antibody-secreting cells were examined in naturally Bothriocephalus acheilognathi-infected carp. Cyprinus carpio, and in those injected intraperitoneally with an extract of the cestode. In the extract-injected fish, specific antibody was detected 3 weeks after a second injection given 2 weeks after the primary injection, and antibody levels persisted for more than 200 days. A third injection also enhanced the antibody level in the extract-injected carp. The numbers of antibody-secreting cells were significantly higher in carp injected 3 times with the extract than in the control. In naturally-infected fish, the serum antibody levels and the number of pronephric antibody-secreting cells were higher in infected fish than in uninfected individuals although this difference was not statistically significant. The relevance of these results to immune protection against infection is discussed.

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Effect of cat litters on feline coronavirus infection of cell culture and cats

Journal of Feline Medicine and Surgery ◽

10.1177/1098612x19848167 ◽

2019 ◽

Vol 22 (4) ◽

pp. 350-357 ◽

Cited By ~ 6

Author(s):

Diane Addie ◽

Lene Houe ◽

Kirsty Maitland ◽

Giuseppe Passantino ◽

Nicola Decaro

Keyword(s):

Cell Culture ◽

Virus Infection ◽

Real Life ◽

In Vitro Study ◽

Oral Route ◽

Virus Shedding ◽

Virus Load ◽

Fuller’S Earth ◽

Feline Coronavirus

Objectives Feline infectious peritonitis (FIP) is caused by infection with feline coronavirus (FCoV). FCoV is incredibly contagious and transmission is via the faecal–oral route. FCoV infection, and therefore FIP, is most common in breeder and rescue catteries, where many cats are kept indoors, using litter trays. Whether it is possible to break the cycle of FCoV infection and reinfection using cat litters has never been investigated. The aim of the study was to examine the effect of cat litters on FCoV infectivity and virus load in multi-cat households, and transmission frequency. Methods Fifteen cat litters were mixed and incubated with FCoV, centrifuged and the supernatants tested in vitro for the ability to prevent virus infection of cell culture. To test applicability of in vitro results to real life, virus load was measured in two households in a double crossover study of four Fuller’s earth-based cat litters by testing rectal swabs using FCoV reverse transcriptase quantitative PCR. Results Four litters abrogated FCoV infection of cell culture, nine reduced it to a greater or lesser extent and two had no effect. One brand had different virus inhibitory properties depending on where it was manufactured. Fuller’s earth-based litters performed best, presumably by adsorbing virus. In the field study, there appeared to be less virus shedding on one Fuller’s earth-based cat litter. Conclusions and relevance The in vitro study successfully identified cat litters that inactivate FCoV; such litters exist so do not need to be developed. Fuller’s earth-based litters best prevented infection of cell culture, but did not completely abrogate FCoV transmission in two multi-cat households. A dust-free clumping Fuller’s earth litter appeared to fare best, but virus shedding also varied on the control litters, complicating interpretation. Sawdust-based cat litters are not useful in FCoV-endemic households because they track badly and have a poor effect on virus infection.

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Low Immunogenicity of Intravesical Phage Therapy for Urogenitary Tract Infections

Antibiotics ◽

10.3390/antibiotics10060627 ◽

2021 ◽

Vol 10 (6) ◽

pp. 627

Author(s):

Sławomir Letkiewicz ◽

Marzanna Łusiak-Szelachowska ◽

Ryszard Międzybrodzki ◽

Maciej Żaczek ◽

Beata Weber-Dąbrowska ◽

...

Keyword(s):

Clinical Trial ◽

Bacterial Infections ◽

Phage Therapy ◽

Serum Antibody ◽

Multidrug Resistant ◽

Antibody Responses ◽

Urogenital Infections ◽

Reliable Model ◽

Tract Infections ◽

Antibody Levels

Patients with chronic urinary and urogenital multidrug resistant bacterial infections received phage therapy (PT) using intravesical or intravesical and intravaginal phage administration. A single course of PT did not induce significant serum antibody responses against administered phage. Whilst the second cycle of PT caused a significant increase in antibody levels, they nevertheless remained quite low. These data combined with good therapy results achieved in some patients suggest that this mode of PT may be an efficient means of therapy for urogenital infections and a reliable model for a clinical trial of PT.

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