Dissociation of the protective immune response in the mouse to Strongyloides ratti

1989 ◽  
Vol 63 (4) ◽  
pp. 307-314 ◽  
Author(s):  
David I. Grove ◽  
Carolyn Northern
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Larval Stage ◽  
Protective Immunity ◽  
Natural Infection ◽  
Cross Reactivity ◽  
Protective Immune Response ◽  
The Other ◽  
Infective Larvae ◽  
Other Hand

ABSTRACTThe generation of protective immunity by various stages in the life-cycle of Strongyloides ratti and the phases against which resistance is directed has been examined in murine strongyloidiasis. Mice were exposed to natural, complete infections, were treated with thiabendazole (which largely resembles the natural infection), were treated with cambendazole (which restricts infection to the larval stage), or infected directly by oral transfer of adult worms. Mice that were infected with infective larvae alone did not become resistant to infective larvae or the complete infection but were resistant to adult worms implanted directly into the gut. Mice exposed to adult worms alone were resistant to natural infections and adults worms implanted directly but were not resistant to infective larvae. On the other hand, mice that had received prior natural infections showed evidence of resistance to infective larvae, adult worms, and natural, complete infections. It is concluded that there is immunological cross-reactivity between infective larvae and adult worms but that under certain circumstances the infective larvae are able to evade the host's protective immune response.

Lipopolysaccharide: a tool and target in enterobacterial vaccine development

2008 ◽  
Vol 389 (5) ◽  
Author(s):  
Gábor Nagy ◽  
Tibor Pál
Keyword(s):  
Immune Response ◽  
Protective Immunity ◽  
Vaccine Development ◽  
The Other ◽  
Live Vaccine Strain ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Vaccination Strategies ◽  
Optimal Balance ◽  
Alternative Approaches

AbstractLipopolysaccharide (LPS) is an essential component of Gram-negative bacteria. While mutants exhibiting truncated LPS molecules are usually over-attenuated, alternative approaches that affect the extent or timing of LPS expression, as well as its modification may establish the optimal balance for a live vaccine strain of sufficient attenuation and retained immunogenicity. On the other hand, a specific immune response to LPS molecules in itself is capable of conferring protective immunity to certain enterobacterial pathogens. Therefore, purified LPS derivatives could be used as parenteral vaccines. This review summarizes various LPS-based vaccination strategies, as well as approaches that utilize LPS mutants as whole-cell vaccines.

scholarly journals The influence of desiccation and UV radiation on the development and survival of free-living stages of cyathostomins under field and laboratory conditions

2008 ◽  
Vol 45 (1) ◽  
pp. 32-40 ◽  
Author(s):  
I. Langrová ◽  
I. Jankovská ◽  
J. Vadlejch ◽  
M. Libra ◽  
A. Lytvynets ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Field Experiments ◽  
The Other ◽  
Infective Stage ◽  
Free Living ◽  
Infective Larvae ◽  
Laboratory Conditions ◽  
Other Hand ◽  
Field And Laboratory Conditions

AbstractThe present work describing both laboratory and field experiments was performed to assess the effects of desiccation and UV radiation on the development and survival of free-living stages of equine cyathostomins.Cyathostomin larvae in horse faeces did not develop to the infective stage when faecal humidity levels dropped below 23 %, nonetheless solitary preinfective larvae were still recovered after 151 days (humidity 19.5 %). The development to infective stage after remoistening occurred for the last time after 54 days following desiccation.Preinfective stages are susceptible to the effects of the direct desiccation stage. The preinfective larvae were rapidly killed within one minute, the cyathostomin eggs within 5 hours. The numerous normal mobile infective larvae were encountered after 35 days of the desiccated period. The preinfective stage of cyathostomins also showed very little tolerance to direct sun radiation: most eggs were killed by the exposure within 3 hours and the preinfective larvae within 1 hour. The survival of infective larvae was, on the other hand, unaffected by sun radiation after 7 days (P < 0.05). However, desiccated infective larvae were then found to be susceptible to UV radiation, resulting in total mortalities after 5 days.

scholarly journals Trickle infection and immunity toTrichuris muris

2019 ◽  
Author(s):  
Maya Glover ◽  
Stefano A.P. Colombo ◽  
David J. Thornton ◽  
Richard K. Grencis
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Protective Immunity ◽  
Helminth Infection ◽  
Natural Infection ◽  
Cd4 T Cell ◽  
Intestinal Helminth ◽  
Low Doses ◽  
Trichuris Muris ◽  
Development Of Resistance

AbstractThe majority of experiments investigating the immune response to gastrointestinal helminth infection use a single bolus infection. However,in situindividuals are repeatedly infected with low doses. Therefore, to model natural infection, mice were repeatedly infected (trickle infection) with low doses ofTrichuris muris. Trickle infection resulted in the slow acquisition of immunity reflected by a gradual increase in worm burden followed by a partial expulsion. Flow cytometry revealed that the CD4+ T cell response shifted from Th1 dominated to Th2 dominated, which coincided with an increase in Type 2 cytokines. The development of resistance following trickle infection was associated with increased worm expulsion effector mechanisms including goblet cell hyperplasia, Muc5ac production and increased epithelial cell turn over. Depletion of CD4+ T cells reversed resistance confirming their importance in protective immunity following trickle infection. In contrast, depletion of group 2 innate lymphoid cells did not alter protective immunity.T. muristrickle infection resulted in a dysbiotic mircrobiota which began to recover alpha diversity following the development of resistance.These data support trickle infection as a robust and informative model for analysis of immunity to chronic intestinal helminth infection more akin to that observed under natural infection conditions and confirms the importance of CD4+ T cell adaptive immunity in host protection.Author SummaryInfection with parasitic worms (helminths) is a considerable cause of morbidity in humans. Understanding how we respond to infection is crucial to developing novel therapies. Laboratory models of helminth infection have been a valuable tool in understanding fundamental immune responses to infection. However, typically an individual mouse will be infected with a large, single-dose of the parasite. This is in contrast to the natural scenario in which individuals will receive frequent low level exposures. What is unknown is how repeated infection alters the development of immunity to infection. We have developed a laboratory model to tackle this question. We infected mice with the model helminthTrichuris murison a weekly basis and assessed a range of responses in comparison with a more traditional infection system. We found striking differences in the dynamics of the infection, the host immune response, and in changes to host gut microbial populations. Our study shows how resistance to helminth infection can develop over time in response to repeat infection, and provides a model system that better reflects human immunity to this parasite.

THE EFFECTS OF SUPERNUMERARY CHROMATIN IN THREE SPECIES OF GRASSHOPPER

1974 ◽  
Vol 16 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Gilbert L. Schroeter ◽  
Godfrey M. Hewitt
Keyword(s):  
Life Cycle ◽  
Chiasma Frequency ◽  
Genetic Material ◽  
B Chromosomes ◽  
Population Variability ◽  
The Other ◽  
Direct Effects ◽  
Apparent Effect ◽  
Other Hand ◽  
The Mean

The chiasma frequencies in males of three species of grasshopper with and without B-chromosomes and supernumerary segments were scored at diplotene. The partially heterochromatic B's found in some individuals of Chimarocephala pacifica pacifica have no effect on chiasma frequencies. On the other hand, heterochromatic supernumerary segments in Oedaleonotus phryneicus males significantly increase the mean chiasma frequencies over individuals without them but not the between-cell variances. In Camnula pellucida neither the mitotically unstable B's nor supernumerary segments have any apparent effect on chiasma.frequencies. The supernumerary elements in Chimarocephala pacifica and Camnula pellucida may, however, produce other effects during the life cycle These and previous observations suggest that polymorphism involving extra genetic material in grasshoppers can result in increased population variability via two different means: (1) by producing variation in chiasma frequency or (2) through direct effects in the individuals possessing it. The importance of such a mechanism for producing variation is discussed.

Studies on Anafilaroides rostratus Gerichter, 1949 in Cats: II. The Life Cycle

1959 ◽  
Vol 33 (2-3) ◽  
pp. 109-122 ◽  
Author(s):  
P. Seneviratna
Keyword(s):  
Life Cycle ◽  
Natural Infection ◽  
Helix Aspersa ◽  
Stomach Wall ◽  
Stage Larva ◽  
Achatina Fulica ◽  
Infective Larvae ◽  
The Third ◽  
One Year ◽  
Gravid Females

The first stage larva of Anafilaroides rostratus develops, after penetration into the foot of certain molluscs, Laevicaulis alte Fer. Mariella dussumieri Gray, Achatina fulica (Fer.) and Helix aspersa Müller. Two moults occur in the foot of these molluscs in 20–56 days depending on the temperature. After each moult the cuticle is shed. The details of development are described. The infective larvae are found in the foot of these molluscs. Natural infection was found in L. alte.Mice and chickens can act as auxiliary hosts. Probably rats, other rodents and birds can also act in the same capacity.The study of the development of the parasite in the cats is not complete. On ingestion the infective larvae penetrate the stomach wall and reach the lung where the third and the fourth moults occur. Exact times of the occurrence of the moults have not been definitely established. All moults are however completed by the 46th day; from then until the 58th day, immature helminths are found in the lungs. Fully gravid females are found on the 74th day, and larvae are first seen on the 78th day. The worms continue to produce larvae for more than 255 days after maturity. The duration of the life of the adult is probably considerably longer than one year.

scholarly journals Cold Reacting Antibody in NZB/Bl Mice

Blood ◽  
1970 ◽  
Vol 35 (5) ◽  
pp. 583-590 ◽  
Author(s):  
NICOLAS COSTEA ◽  
VINCENT YAKULIS ◽  
PAUL HELLER
Keyword(s):  
Immune Response ◽  
Infectious Agent ◽  
The Other ◽  
Mouse Spleen ◽  
Intact Mouse ◽  
Other Hand ◽  
Mouse Tissues ◽  
Erythrocyte Antigen

Abstract NZB/Bl mice produce throughout life cold reacting antibodies (CRA) with specificity to the I-erythrocyte antigen. These antibodies do not react with autologous erythrocytes since intact mouse erythrocytes do not carry reactive I-antigen. This antigen on the other hand is widely distributed in NZB/Bl mouse tissues. Newborn CF1 mice injected with cell-free filtrates of NZB/Bl mouse spleen produce CRA. The untreated offspring of these animals also synthesize this type of antibody suggesting that this immune response is induced by a self-replicating, ultrafilterable immunogen. CRA in NZB/Bl mice may, therefore, be another example of the induction of an auto-immune response by an infectious agent.

scholarly journals Sustainability in Clusters: Proposal of a Conceptual Model

2013 ◽  
Vol 12 (3) ◽  
pp. 212-241
Author(s):  
Fabiano Larentis ◽  
Rafael Giovanella ◽  
Tatiane Pellin Cislaghi
Keyword(s):  
Life Cycle ◽  
Conceptual Model ◽  
Knowledge Creation ◽  
The Other ◽  
Governance Mechanisms ◽  
Other Hand ◽  
Exploitation And Exploration ◽  
Reducing Costs ◽  
The Relationship

The growing industrial restructure and movements of cooperation, increase pressures by reducing costs and increasing productivity, thus it has generated the formation of new arrangements between the companies, with focus on clusters. The clusters are formed when the similar areas and geographical aspects are concentrated and where the expertise and innovation are essential for companies to reach markets beyond their borders. On the other hand, one of the challenges in developing a cluster is related to its sustainability, in the economic, social and environmental dimensions. Thus, in this essay, we propose a conceptual model that addresses the relationship between clusters and sustainability, taking into account the perspective of networks. Such a model, spiral shaped, involves basic (actors, governance mechanisms, resources and location), intermediate (cluster strength and openness, integration and adaptation, knowledge creation / inventory and movement, exploitation and exploration actions) and resulting aspects (performance and sustainability of the cluster), in a context of life cycle and environmental dynamics.

scholarly journals Development and validation of an enzyme immunoassay for detection and quantification of SARS-CoV-2 salivary IgA and IgG

2021 ◽  
Author(s):  
Veronica Costantini ◽  
Kenny Nguyen ◽  
Zoe Lyski ◽  
Shannon Novosad ◽  
Ana C Bardossy ◽  
...  
Keyword(s):  
Immune Response ◽  
Enzyme Immunoassay ◽  
Limit Of Detection ◽  
Natural Infection ◽  
High Specificity ◽  
Cross Reactivity ◽  
Igg Antibodies ◽  
Antibody Isotype ◽  
Salivary Iga ◽  
Specificity And Sensitivity

Oral fluids offer a non-invasive sampling method for the detection of antibodies. Quantification of IgA and IgG antibodies in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG antibodies against the prefusion-stabilized form of the SARS-CoV-2 spike protein. Normalization against total antibody isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 pre-pandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA: 95.5%; IgG: 89.7%) without compromising specificity (IgA: 99%; IgG: 97%). No cross reactivity with seasonal coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/mL and 0.30 ng/mL, respectively. Salivary IgA and IgG antibodies were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary antibody titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 weeks in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.

scholarly journals Protection Efficacy of the rLTB-R1 Chimera against Experimental Swine Mycoplasmal Pneumonia

2019 ◽  
Vol 47 (1) ◽  
Author(s):  
Marcos Roberto Alves Ferreira ◽  
Paula Fonseca Finger ◽  
Carolina Georg Magalhães ◽  
Carlos Eduardo Pouey da Cunha ◽  
Clóvis Moreira Júnior ◽  
...  
Keyword(s):  
Immune Response ◽  
The Other ◽  
Pulmonary Lesion ◽  
Control Group ◽  
Swine Industry ◽  
Whole Cells ◽  
Other Hand ◽  
Specific Pathogen ◽  
Mycoplasmal Pneumonia ◽  
Trachea And Bronchi

Background: Mycoplasma hyopneumoniaeis the etiological agent of the Swine Mycoplasmal Pneumonia (SMP), one of the most economically significant diseases in the swine industry worldwide. Commonly used vaccines for SMP control consist of inactivated whole cells (bacterins). These vaccines are efficacious against M. hyopneumoniaechallenge, but do not prevent colonization by the pathogen or completely eliminate pneumonia. P97 adhesin is conserved in the M. pneumoniae virulent strains, therefore it is an attractive target to be used in recombinant vaccines against M. hyopneumoniae. The aim of the present study was to evaluate protection afforded by rLTB-R1, a recombinant chimera composed by LTB fused with the R1 repeat region of P97 adhesin of M. hyopneumoniae, in specific-pathogen-free (SPF) piglets vaccinated by intranasal or intramuscular route and challenged with a pathogenic strain of M. hyopneumoniae.Materials, Methods & Results:PCR products of the LTB and R1 coding sequences were fused, then cloned into pETDEST42™ expression vector. The rLTB-R1 was expressed in Escherichia coli BL21 (DE3) Salt induction (SI).They were allocated into three groups: four piglets were intranasally vaccinated with 1 mg of rLTB-R1 solubilized in 1 mL of PBS at 0 and 14 days (IN rLTB-R1 group); four piglets were intramuscularly vaccinated with 1 mg of rLTB-R1 solubilized in 1 mL of PBS at 0 and 14 days (IM rLTB-R1 group);three piglets were intranasally and intramuscularly inoculated with 1 mL of PBS (control group).Two weeks after the last immunization (28 day), piglets were intratracheally challenged with 10 mL of a suspension containing 109color-changing unit (CCU) of pathogenic M. hyopneumoniae 7448 strain on three consecutive days. Until the challenge (28 days), intranasal and intramuscular vaccination with rLTB-R1 induced seroconversions of anti-R1 systemic antibodies of 1.6 and 4.6 ×, respectively. The IN rLTB-R1 group had no pulmonary lesion, rLTB-R1 conferred protection against experimental SMP. On the other hand, IM rLTB-R1 and control groups had on average 7.24% and 8.46% of pulmonary lesion, respectively, showing that intramuscular vaccination with rLTB-R1 did not confer protection.Discussion:The rLTB-R1, when intranasally administrated to mice, elicited production of anti-R1 IgA in trachea and bronchi as well as specific Th1 response, suggesting an adequate stimulation of the mucosal immune system. We believe that rLTB-R1 induced a similar immune response in piglets intranasally vaccinated, conferring protection against experimental SMP. The present study, the rLTB-R1 alone, without any chemical adjuvant, stimulated a significant seroconversion of anti-R1 systemic antibodies in pigs intramuscularly vaccinated, showing the potential of LTB as a parenteral adjuvant in swine vaccination.Previous work has shown that the intramuscular administration route was evaluated in pigs because mice intramuscularly vaccinated with rLTB-R1 presented significant levels of anti-R1 IgA in trachea and bronchi, suggesting that rLTB can stimulate some degree of mucosal immunity even if not delivered by a mucosal route.However, in the present study, piglets intramuscularly vaccinated with rLTB-R1 presented high levels of anti-R1 systemic antibodies, they were not protected.On the other hand, intranasal vaccination of piglets with rLTB-R1 elicited low levels of anti-R1 systemic antibodies (1.6 × at 28 days), but it conferred full protection against experimental SMP. The present study demonstrated that intranasal vaccination of piglets with rLTB-R1 conferred protection against experimental SMP. A more detailed analysis of the protective immune response induced by rLTB-R1 in pigs is currently being performed.

scholarly journals Ecto and Endo Parasites Prevalence in Domestic Chickens in Sulaimani Region

2013 ◽  
Vol 37 (2) ◽  
pp. 149-155
Author(s):  
Shadan Hassan Abdullah
Keyword(s):  
Larval Stage ◽  
Parasite Species ◽  
Gallus Domesticus ◽  
The Other ◽  
Soft Tick ◽  
Ascaridia Galli ◽  
Argas Persicus ◽  
Heterakis Gallinarum ◽  
Other Hand ◽  
Internal Parasites

     The study was conducted on 65 local adult chickens (Gallus domesticus) to investigate  macro - and microscopically presence of external and internal parasites and their prevalence in Sulaimani region-Kurdistan/Iraq from May to July 2012. Results showed that 90.77 % out of total examined chickens were infested with ecto-parasites, out of that 81.36 % (48/59) were infested with lice such as (Menacanthus  stramineus, Goniocotes  gallinae, Menopon  gallinae, Goniodes  gigas, Cuclotogaster  heterographus ) and 62.72 (37/59) of it with larval stage of soft tick such as (Argas  persicus).  Mixed infestations with more than two ecto-parasite species were detected. On the other hand 89.23% out of 65 examined chickens were infected by internal parasites including nematodes and cestodes such as (Heterakis  gallinarum which formed 81% and the remains were Ascaridia  galli, Cheilospirura  hamulosa, Capillaria  spp., Raillietina  spp., Choanotaenia  infundibulum, Amoebotaenia  sphenoides, Hymenolepis  carioca and  Davaniea  proglottina).

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