COVID Vaccines

in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highly pathogenic means…

enveloped positive sense, single stranded, non-segmented RNA virus

(+) sense

RNA can act as mRNA and translate into protein

(-) sense

RNA requires conversion to (+) sense then translate into protein

#1 what was overall goal of study? What were the 4 types of immune memory examined?

goal of response was to understand immune memory responses to SARS-CoV-2.

• antibodies

• memory B cells

• CD4+ T cells

• CD8+ T cells

#2 “durability” is mentioned several times; what do you think durability means w/in context of immune memory?

length of time immune memory (SARS-CoV-2-specific immunity) is measured after infection

#3 In Figure 1, IgG + IgA are measured. Why might IgA be important to study in context of SARS-CoV-2 infection (hint: what anatomical regions is IgA associated?

IgA associated w/ humoral immunity at mucosal surfaces, (ex. airway and lung), major sites of SARS-CoV2 infection

#4 what function do circulating T follicular helper (cTfh) cells serve here as it relates to B cells

circulating T follicular helper (cTfh) cells provide:

• B cell help

• support SARS-CoV-2 specific antibody generation

• long-lived humoral immunity

#5 CCR6 + SARS-CoV-2 specific cTfh cells increase over time. What is function of CCR6? What might be happening to cTfh cells that express CCR6?

CCRG6 is chemokine receptor that mediates cell migration into tissue (especially, mucosal tissue: lung and airway).

increase in CCR6+ cTfh may indicate these cells migrating into tissues and providing support of local humoral immune responses

#6 In Figure 56, what do these findings highlight about patterns of immune memory?

immune memory to SARS-CoV-2 infection is heterogenous w/ different patients of immune memory in different individuals

#7 what percentage of patients retained immune memory ~ 6 months after infection? Is durable immunity possible against secondary COVID-19 disease?

95% patients had at least 3 out of 5 immune memory responses at 6-8 months .

yes, durable immunity is possible (but longer studies are needed to determine how long)

how do mRNA vaccines elicit an immune response?

1. intramuscular immunization

2. mRNA.antigen taken up by dendritic cells

3. trafficking to lymph nodes

4. priming of CD4+ T cells (lymphocytes)

5. CD4 activation: if Th1, they will go out into circulation and secrete antibodies

   CD8 activation: exit lymph node and search put virus infected cells

   Both leaves as IFNγ, IL-2, TNF

6. GC reaction (Tfh will migrate to GC reaction to help) development of long lived plasma cells that will secrete antibodies

janssen

replication-defective adenovirus carries gene for SARS-CoV2 spike protein

• cannot replicate or cause infection