How the Johnson & Johnson Vaccine Works

0

Johnson & Johnson is testing a coronavirus vaccine called JNJ-78436735 or Ad26.COV2.S. Results of a clinical study are expected in January.

Janssen Pharmaceutica, a Belgium-based division of Johnson & Johnson, is developing the vaccine in partnership with Beth Israel Deaconess Medical Center.

A piece of the coronavirus

The SARS-CoV-2 virus is filled with proteins that it uses to enter human cells. These so-called spike proteins are a tempting target for potential vaccines and treatments.

The Johnson & Johnson vaccine is based on the virus’ genetic instructions to build the spike protein. Unlike the Pfizer-BioNTech and Moderna vaccines, which store instructions in single-stranded RNA, the Johnson & Johnson vaccine uses double-stranded DNA.

DNA in an adenovirus

The researchers added the gene for the coronavirus spike protein to another virus called adenovirus 26. Adenoviruses are common viruses that typically cause colds or flu-like symptoms. The Johnson & Johnson team used a modified adenovirus that can enter cells but cannot replicate in cells or cause disease.

The Johnson & Johnson vaccine stems from decades of research into adenovirus-based vaccines. In July the first was approved for general use – an Ebola vaccine, also manufactured by Johnson & Johnson. The company is also conducting trials of adenovirus-based vaccines for other diseases such as HIV and Zika. Some other coronavirus vaccines are also based on adenoviruses, like the one developed by the University of Oxford and AstraZeneca using a chimpanzee adenovirus.

Adenovirus-based vaccines against Covid-19 are more robust than mRNA vaccines from Pfizer and Moderna. DNA is not as fragile as RNA, and the adenovirus’ hard protein shell protects the genetic material inside. As a result, the Johnson & Johnson vaccine can be refrigerated at 2 to 8 ° C for up to three months.

Enter a cell

After the vaccine is injected into a person’s arm, the adenoviruses push against cells and cling to proteins on their surface. The cell swallows the virus into a bubble and pulls it inside. Inside, the adenovirus escapes from the bladder and migrates to the nucleus, the chamber in which the cell’s DNA is stored.

Virus devoured

in a bubble

Virus devoured

in a bubble

Virus devoured

in a bubble

The adenovirus pushes its DNA into the nucleus. The adenovirus is designed so that it cannot make copies of itself, but the gene for the coronavirus spike protein can be read by the cell and copied into a molecule called messenger RNA or mRNA.

Structure of spike proteins

The mRNA leaves the nucleus and the cell’s molecules read their sequence and start building spike proteins.

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Three spines

Proteins combine

spikes

and protein

Fragments

Show

Spike protein

Fragments

Some of the spike proteins produced by the cell form spikes that migrate to its surface and their tips stick out. The vaccinated cells also break down into fragments some of the proteins that they present on their surface. These protruding spikes and spike protein fragments can then be recognized by the immune system.

The adenovirus also provokes the immune system by turning on the cell’s alarm systems. The cell sends out warning signals to activate nearby immune cells. By triggering this alarm, the Johnson & Johnson vaccine makes the immune system more responsive to the spike proteins.

Discover the intruder

When a vaccinated cell dies, the debris contains spike proteins and protein fragments, which can then be taken up by a type of immune cell called an antigen-presenting cell.

Present a

Spike protein

fragment

Present a

Spike protein

fragment

Present a

Spike protein

fragment

The cell presents fragments of the spike protein on its surface. When other cells called helper T cells recognize these fragments, the helper T cells can set off the alarm and help other immune cells fight the infection.

Make antibodies

Other immune cells, called B cells, can bump against the coronavirus spikes on the surface of vaccinated cells or against free-floating spike protein fragments. Some of the B cells may be able to bind to the spike proteins. When these B cells are then activated by helper T cells, they start to multiply and pour out antibodies that target the spike protein.

Matching

Surface proteins

Matching

Surface proteins

Matching

Surface proteins

Matching

Surface proteins

Matching

Surface proteins

Matching

Surface proteins

Matching

surface

Proteins

Matching

surface

Proteins

Matching

surface

Proteins

Matching

Surface proteins

Matching

Surface proteins

Matching

Surface proteins

Stop the virus

The antibodies can attach to coronavirus spikes, mark the virus for destruction, and prevent infection by preventing the spikes from attaching to other cells.

Kill infected cells

The antigen presenting cells can also activate another type of immune cell called a killer T cell to search for and destroy any coronavirus infected cells that have the spike protein fragments on their surfaces.

Present a

Spike protein

fragment

Beginning

to kill them

infected cell

Present a

Spike protein

fragment

Beginning

to kill them

infected cell

Present a

Spike protein

fragment

Beginning

to kill them

infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Present a

Spike protein

fragment

I’m starting to kill

the infected cell

Memory of the virus

Johnson & Johnson is testing a single dose of the vaccine, unlike the coronavirus vaccines with two doses from Pfizer, Moderna and AstraZeneca. Because the results of the Johnson & Johnson Phase 3 study have not yet been published, the researchers have no idea how well the vaccine might work or how long it might last to protect.

If the vaccine is effective, it is possible that antibody and killer T-cell counts may decrease in the months following vaccination. However, the immune system also contains special cells, so-called memory B cells and memory T cells, which can store information about the coronavirus for years or even decades.

Vaccination timeline

January 2020 Johnson & Johnson begins work on a coronavirus vaccine.

March Johnson & Johnson will receive $ 456 million from the US government to develop and manufacture the vaccine.

July A phase 1/2 study begins. Unlike the clinical trials for other leading vaccines, the trial is one dose, not two.

A dose of the Johnson & Johnson vaccine.Michael Ciaglo / Getty Images

August The federal government agrees to pay Johnson & Johnson $ 1 billion for 100 million doses if the vaccine is approved.

September Johnson & Johnson starts a phase 3 study.

8th October The European Union has reached an agreement to receive 200 million cans.

12th of October The company is suspending its phase 3 study to investigate a side effect in a volunteer.

23rd October The process continues.

November 16 Johnson & Johnson announces a second Phase 3 study to assess the effects of two doses of their vaccine instead of one.

December 17th Johnson & Johnson announces that the phase 3 study with approximately 45,000 participants is fully enrolled.

January 2021 Preliminary results of the phase 3 study are expected in January. The company aims to produce at least one billion cans by 2021.

February If studies show the vaccine is effective, the company could apply for an emergency clearance with the Food and Drug Administration in February.


Sources: National Center for Information on Biotechnology; Nature; Lynda Coughlan, University of Maryland Medical School.

Chasing the coronavirus

close

WANT MORE?

SIGN UP TO RECEIVE THE LATEST HEALTH FITNESS ,LIFESTYLE TIPS & TRICKS, PLUS SOME EXCLUSIVE GOODIES!

We don’t spam! Read our privacy policy for more info.

Leave A Reply

Your email address will not be published.