COVID-19 booster enhances IgG mediated viral neutralization by human milk in vitro

Background

Facilitated by the inability to vaccinate, and an immature immune system, COVID-19 remains a leading cause of death among children. Vaccinated lactating mothers produce specific SARS-CoV-2 antibodies in their milk, capable of neutralizing the virus in vitro. Our objective for this study is to assess the effect of COVID-19 booster dose on SARS-CoV-2 antibody concentration and viral neutralization in milk, plasma, and infant stool.

Methods

Thirty-nine mothers and 25 infants were enrolled from December 2020 to May 2022. Milk, maternal plasma, and infants' stool were collected at various time-points up to 12 months following mRNA COVID-19 vaccination. A subgroup of 14 mothers received a booster dose. SARS-CoV-2 antibody levels and their neutralization capacities were assessed.

Results

Booster vaccination led to significantly higher IgG levels within human milk and breastfed infants' stool. In vitro neutralization of VSV-gfp-SARS-CoV-2-S-gp, a laboratory safe SARS-CoV-2 like pseudovirus, improved following the booster, with a 90% increase in plasma neutralization and a 60% increase in milk neutralization. We found that post-booster neutralization by human milk was highly correlated to SARS-CoV-2 IgG level. In support of our correlation result, Protein G column depletion of IgG in milk yielded a significant reduction in viral neutralization (p = 0.04).

Discussion

The substantial increase in neutralizing IgG levels in milk and breastfed infants' stool post-booster, coupled with the decrease in milk neutralization capabilities upon IgG depletion, underscores the efficacy of booster doses in augmenting the immune response against SARS-CoV-2 in human milk.

The role of dopaminergic mechanisms in mediating the central behavioral effects of morphine in rodents

Morphine has been universally assumed to act solely on opiate receptors, and predominantly on mu receptors. In consonance with this, several studies have demonstrated that opiate mu agonists and dopaminergic agonists and antagonists are incapable of binding each other's receptors, except at extremely high concentrations (nor, for that matter, are acetylcholine, serotonin, gamma-hydroxybutyrate, norepinephrine or histamine able to bind opiate receptors). Yet, while other neurotransmitter antagonists (e.g. alpha- and beta-adrenoceptor-blocking agents) are for the most part limited in their effect on opiate-induced responses, many of the central effects elicited by morphine and other opioids have been found to be markedly potentiated by dopamine (DA) antagonists and reversed by direct and indirect DA agonists. Even more significantly, DA antagonists (especially those appreciably inhibiting DA release selectively) can also mimic many of these effects in low to moderate doses. Since DA antagonists do not act by binding opiate receptors, it is quite likely that morphine and other opiate mu receptor agonists may at least partially induce many of their acute central effects by means of an inhibition of postsynaptic DA receptor arousal. This appears to be a consequence of morphine binding its own (mu) receptors localized on central DA nerve terminals, resulting in an alteration of presynaptic DA release. This review does not exclude the important role of other neurotransmitter substances in the action of morphine, but rather emphasizes, and limits itself to considering, the importance of the role of dopamine in morphine-induced behaviors.

Effect of naloxone and morphine on dopamine agonist-induced stereotypy in rats and guinea pigs

Naloxone (0.80 mg/kg) and morphine (7.5 mg/kg) were given to rats or guinea pigs with increasing doses of amphetamine (0.5-6.0 mg/kg) to determine their respective effects on amphetamine-induced stereotypy. In contrast to the inhibiting and potentiating effect of these agents on apomorphine-induced stereotyped behavior, naloxone enhanced and morphine markedly attenuated amphetamine-induced stereotypy. Since other investigators have reported that drugs inhibiting release of dopamine block amphetamine-induced stereotypy and enhance apomorphine-induced stereotypy, whilst compounds stimulating the release of dopamine potentiate amphetamine-induced stereotypy and inhibit apomorphine-elicited stereotyped behavior, it is likely that naloxone stimulates and morphine inhibits the release of DA following their acute administration.

Differential catecholamine uptake inhibition as a possible mode of action of D-amphetamine induced locomotor activity

A determination was made of the roles played by the selective uptake inhibition versus release of dopamine (DA) or norepinephrine (NE) ex vivo in either the striatum or cerebral cortex in mediating d-amphetamine induced locomotor activity (AILA). Desmethylimipramine (DMI) and/or d-amphetamine variously effected the uptake of DA and NE in both regions in terms of the absolute amount of uptake inhibition elicited by each drug separately or by the two drugs administered concomitantly. However, none of the drug treatments produced a selective inhibition of DA or NE uptake in either the striatum or cerebral cortex. On the other hand, a selective inhibition of central DA release by gamma-hydroxybutyrate markedly inhibited AILA. These results suggest that amphetamine induced locomotor activity is not likely mediated by a preferential effect on DA or NE uptake. It is far more probable that AILA is induced by a stimulation of central DA release.

The combined effect of quipazine and haloperidol on plasma prolactin release

The possible dopaminergic properties of the central serotonergic agonist quipazine was examined using plasma prolactin release as a model to determine whether quipazine exerts an agonist effect on only serotonin receptors or on dopamine receptors as well. Drugs acting on two different receptors have only an additive effect on the same parameter while different drugs acting on the same receptor exert a synergistic effect. Therefore we determined whether combining quipazine with haloperidol, which has no effect on serotonin receptors, would produce a synergistic or only an additive effect on prolactin release, relative to the release induced by quipazine alone. A distinct synergism was produced, suggesting that quipazine acts on both DA and 5-HT receptors. Moreover, the model used may be useful for distinguishing whether a given drug acts on one or two receptors concurrently.

Possible DA agonist properties of naloxone

Naloxone is widely if not universally considered to be a pharmacologically 'pure' opiate (mu) receptor antagonist virtually devoid of agonist action when administered in moderate dosages. However, naloxone (NX) appears to possess a striking number of DA agonist properties. Thus, some investigators have found NX capable of inducing stereotyped rearing and locomotor activity in habituated rats (a controversial finding), and decrease serum prolactin levels, improve Parkinsonism, enhance copulatory performance in sexually sluggish animals, and increase striatal HVA levels, in mimicry of centrally acting DA agonists. NX can also significantly potentiate the central effects induced by DA agonists including DA agonist (d-amphetamine) induced 3H-dopamine release, and antagonize a number of the central effects elicited by DA release inhibiting agents. Finally, virtually all of the central effects of morphine reversible by NX have also been found to be antagonized by a variety of dopamine agonists; while DA release inhibiting agents can abolish the ability of NX to antagonize morphine induced effects. Thus, NX may be exerting its central effects through a dopaminergic mechanism. Since NX does not bind DA receptors, it is quite likely that NX may ultimately antagonize the central effects of morphine by enhancing DA release from DA terminals upon which opiate receptors are localized. The same opiate receptors, shown to be localized on DA nerve terminals, have already been implicated in opiate mediated modulation of DA release.

Metaphyseal giant-cell tumor in a girl of 14

A case of giant-cell tumor in the radial metaphysis of a 14-year-old girl is reported. 3.5% of these tumors are detected in patients younger than 15 years of age, when closure of the cartilaginous growth plate occurs. A significant number of the 14% of giant-cell tumors detected in patients younger than 20 may originate in a metaphysis during adolescence and become symptomatic only after long bone epiphyseal involvement.

Myelopathy simulating spinal cord tumor

Three cases of demyelinating or necrotizing myelopathy are presented in which gradual onset of symptoms, slowly progressive course and widened cord shadow on myelography led to the erroneous diagnosis of intramedullary spinal cord neoplasm. Two of the cases also had inconclusive surgical explorations. We would suggest that patients who seem to have even a typical clinical and myelographic picutre of an intrinsic cord neoplasm have a period of further observation before radiotherapy is begun and that a vigorous search be made for evidence of disseminated disease.

Thiolases of Escherichia coli: purification and chain length specificities

The presence of only one thiolase (EC 2.3.1.9) in wild-type Escherichia coli induced for enzymes of beta oxidation was demonstrated. A different thiolase was shown to be present in a mutant constitutive for the enzymes of butyrate degradation. The two thiolases were purified to near homogeneity by a simple two-step procedure and were found to be associated with different proteins as shown by gel electrophoresis. The thiolase isolated from induced wild-type Escherichia coli cell was active on beta-ketoacyl-coenzyme A derivatives containing 4 to 16 carbons, but exhibited optimal activity with medium-chain substrates. In contrast, the thiolase isolated from the constitutive mutant was shown to be specific for acetoacetyl-coenzyme A.

ABDOMINAL HODGKIN'S DISEASE

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