Familial hemophagocytic lymphohistiocytosis (HLH) is

Hypersecretion of luteinizing hormone (LH) is implicated in infertility and miscarriages in women. A lack of animal models has limited progress in determining the mechanisms of LH toxicity. We (7)], it is difficult to devise protocols for chronic administration of exogenous LH that mimic endogenous pulse patterns of LH. To circumvent this limitation, we report a transgenic mouse model in which elevated hormone levels are maintained chronically, without requiring multiple injections,The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. supraphysiologic dosing, or dampening of the hypothalamicpituitary-gonadal axis.We utilized a two-pronged approach to achieve elevated levels of serum LH. (i) Increased secretion of hormone from the pituitary was achieved by expression of an LH(3 subunit transgene, targeted to the pituitary by a previously characterized bovine a-subunit promoter (8,9). (ii) The LH,B transgene was modified to encode a peptide extension that we proposed would slow the elimination of LH from the serum. This peptide is normally found at the C terminus of the 3 subunit of human chorionic gonadotropin (hCG) (hCG,B) and is referred to as the C-terminal peptide (CTP) (10). The CTP is thought to be a major determinant of the serum t,'2 of hCG and has been shown to increase the til2 of FSH 2-to 3-fold when fused to its (3 subunit (11). Accordingly, we constructed a transgene with the coding region of bovine (b) LH,B fused in-frame to the coding region of CTP (bLH3-CTP). MATERIALS AND METHODSConstruction of the bLH3-CTP Transgene. The bLH,B-CTP minigene was engineered by a two-step PCR. (i) A short fragment containing the C terminus of bLH,B (30 bp) fused in-frame to the CTP (last 87 bp of the hCGj3 gene) was generated. (ii) This fragment was lengthened to contain the entire bLHf3 cDNA fused in-frame to the CTP. This fusion gene was utilized for transfection experiments but was modified to contain the first intron of bLH3 for the transgene construct. The resulting insert was ligated into a BSK-plasmid already containing the bovine a-subunit promoter (positions -315 to +45) and the simian virus 40 late polyadenylylation signal. Transgenic mice were generated by microinjecting the bLH3-CTP insert into fertilized oocytes as described (12). Mice were genotyped by PCR analysis of tail DNA using primers specific to the a-subunit promoter and (3-subunit gene.Analysis of t,,2. Recombinant bLH and bLH-CTP heterodimers were generated by stably cotransfecting CHO cells with viral expression vectors containing the bovine a-subunit gene and either the bLH( or bLH,3-CTP genes as described (13). Serum-free medium was collected and ammonium sulfate-precipitated or concentrated with an Amicon ultrafiltration cell. Female rats were pretreated with 50 ,tg of antide (Sigma) in 20% (vol/vol) propylene glycol, injected subcutaneously 2 h prior to hormone injections t...

Anaphylaxis to vaccines is historically a rare event. The Coronavirus Disease 2019 (COVID-19) pandemic drove the need for rapid vaccine production applying a novel antigen delivery system: mRNA vaccines packaged in lipid nanoparticles (LNP). Unexpectedly, public vaccine administration led to a small number of severe allergic reactions with resultant substantial public concern, especially within atopic individuals. We reviewed the constituents of the mRNA LNP vaccine and considered several contributors to these reactions: 1) contact system activation by nucleic acid, 2) complement recognition of the vaccine activating allergic effector cells, 3) pre-existing antibody recognition of polyethylene glycol (PEG), a LNP surface hydrophilic polymer, and 4) direct mast cell activation, coupled with potential genetic or environmental predispositions to hypersensitivity. Unfortunately, measurement of anti-PEG antibodies in vitro is not clinically available, and the predictive value of skin testing to PEG components as a COVID-19 mRNA vaccine-specific anaphylaxis marker is unknown. Even less is known regarding the applicability of vaccine use for testing (in vitro/vivo) to ascertain pathogenesis or predict reactivity risk. Expedient and thorough research-based evaluation of patients who have suffered anaphylactic vaccine reactions and prospective clinical trials in putative at-risk individuals are needed to address these concerns during a public health crisis.