The Development of a COVID19 Oral Vaccine Consisting of Bacillus Subtilis Spores

Not Applicable

Completed

Conditions: COVID-19 Pneumonia

Interventions: Biological: Bacillus subtilis

Registration Number: NCT05057923

Lead Sponsor: DreamTec Research Limited

Brief Summary: This is a study trial to assess the effectiveness of the immune response stimulated by the genetically engineered Bacillus subtilis which express and display Spike protein of the SARS-COV2 on the spore coat.

Detailed Description: Bacillus subtilis is regarded as safe organism by The Food and Drug Administration and it is presented in most food sources. Preliminary experiments have shown that the genetically engineered Bacillus subtilis can express and display receptor binding domain of spike protein of the SARS-COV2 on its spore coat, thus successfully induce the secretion of cytokines of human cells in vitro. Previous experiments also successfully demonstrated that a increased detection of neutralizing IgG and igM levels in mice after oral administrated with the Bacillus subtilis. This suggests that the transgenic spores of Bacillus subtilis have successfully activated the immune system, producing high-affinity neutralizing antibodies and memory B cells. Furthermore, no adverse effects were shown in all the mices. The engineered Bacillus subtilis will be further studied in a human trials through oral administration to test its safety and the immune effect resulted in human bodys.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 9

Inclusion Criteria

healthy
age over 25 years
the outcome of the following examinations should be clinically insignificant: medical and surgical history (hypo-, hypertension, allergy, other diseases, major surgery, micturition, defecation, sleep, illness within the last 4 weeks prior to the start of the trial);
participant vaccinated with Sinovac over 4 months
anti-SARS CoV 2 neutralizing antibody is negative in serum.

Exclusion Criteria

pregnant women
history of COVID-19 infection or showing COVID-19 infection symptoms
having had contact to people with known COVID-19 infection in the last 14 days
having fever (> 37.4oC in the last 24 hours), dry cough or feeling tired and having aches and pains, nasal congestion, runny nose, sore throat and diarrhea.
positive real time RT-PCR COVID-19 test.
persons with autoimmune diseases
allergic diathesis or any clinically significant allergic disease (i.e. asthma)
any condition that might impair the immune response
recent or current immunosuppressive medication
any other vaccine application 30 days before the first dose

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
generation of neutralizing antibody for unvaccinated participants	Bacillus subtilis	participants received vaccine 1 capsule of 1×10\^10 CFU of B. subtilis spore at day 0, 14, and 28 respectively.
neutralizing antibody booster for vaccinated participants	Bacillus subtilis	participants after 4-month vaccinated with Sinovac received 1 capsule of 1×10\^11 CFU of B. subtilis spore

Primary Outcome Measures

Name	Time	Method
Serum Neutralizing Receptor Binding Domain IgG Antibody Concentration	Day 0, 27, 42 post oral administration	Concentration of neutralizing IgG antibody against receptor binding domain of spike protein in SARS-COV2

Secondary Outcome Measures

Name	Time	Method
Lentirival Pseudovirus Neutralization Assay (Wild Type of SARS-CoV2)	Day 0, 27, 42 post oral administration	The ability of neutralization against SARS-CoV-2 was tested by an in vitro pseudo-virus neutralization assay. The lentivirus carrying a GFP gene was pseudotyped with the spike protein from a wild type of SARS-CoV-2. The pseudoviruses were then pre-incubated with serially diluted serum samples from orally vaccinated volunteers before being added to A549 lung carcinoma cells expressing human ACE2 and human TMPRSS2. The percentage of infection rate was measured with a fluorescent plate reader by counting GFP-positive cells. The results were fitted with a non-linear regression model. The dilution of the serum sample resulted in a 50% reduction of infection rate is designated as EC50. The results were presented as "NA" when the serum samples failed to neutralize pseudovirus infection.
Lentirival Pseudovirus Neutralization Assay (D614G SARS-COV2 Variant)	Day 0, 27, 42 post oral administration	The ability of neutralization against SARS-CoV-2 was tested by an in vitro pseudo-virus neutralization assay. The lentivirus carrying a GFP gene was pseudotyped with the spike protein from a D614G variant of SARS-CoV-2. The pseudoviruses were then pre-incubated with serially diluted serum samples from orally vaccinated volunteers before being added to A549 lung carcinoma cells expressing human ACE2 and human TMPRSS2. The percentage of infection rate was measured with a fluorescent plate reader by counting GFP-positive cells. The results were fitted with a non-linear regression model. The dilution of the serum sample resulted in a 50% reduction of infection rate is designated as EC50. The results were presented as "NA" when the serum samples failed to neutralize pseudovirus infection.