Introduction

Hemagglutination (HA) and hemagglutination inhibition (HI) assays are conventionally used for the detection and identification of influenza viruses, using red blood cells (RBCs) from mammalian and avian sources. However, there could be limitations for availability of fresh RBCs due to situations such as pandemics, public health emergencies, outbreaks in avian species, lack of animal facilities, animal ethics concerns; or resource-constrained laboratories, and laboratories which do not carry out HA and HI assays routinely. Turkey RBCs (tRBCs) are widely used for HA and HI assays of influenza viruses. The present study explored the possibility of the use of glutaraldehyde-fixed tRBCs, which could be stored at -80 ^ºC and readily used for HA and HI assays.

Materials and methods

A total of nine subtypes of human and avian influenza viruses, A H1N1, H3N2, H4N6, H5N1, H6N1, H7N9, H9N2, H11N1 and type B, were used in the study. Turkey RBCs were fixed with glutaraldehyde. The HA and HI assays were performed three times by two different operators using fresh and glutaraldehyde fixed tRBCs. The significance of difference in HA and HI titers between fixed and fresh RBCs was compared using ‘t-test’. The performance of fixed RBCs was evaluated before and after storing at -80 ^ºC for three weeks.

Results

There was no significant difference (p > 0.05) between mean HA and HI titers using fresh and glutaraldehyde-fixed turkey RBCs. In addition, the HA and HI titers using fixed tRBCs before and after storing at -80 ^ºC were equivalent, indicating suitability of the fixed and stored RBCs.

Conclusions

This is the first report of the use of fixed and stored tRBCs for HA and HI assays of influenza viruses, highlighting their applicability as a ready-to-use reagent for laboratory diagnosis of influenza.

中文翻译：

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冷冻保存的戊二醛固定火鸡红细胞在血凝和血凝抑制试验中的应用在流感病毒的检测和鉴定中

介绍

血凝 (HA) 和血凝抑制 (HI) 测定通常用于检测和鉴定流感病毒，使用来自哺乳动物和鸟类的红细胞 (RBC)。然而，由于流行病、突发公共卫生事件、禽类爆发、缺乏动物设施、动物伦理问题等情况，新鲜红细胞的供应可能会受到限制；或资源有限的实验室，以及不定期进行 HA 和 HI 检测的实验室。土耳其红细胞 (tRBC) 广泛用于流感病毒的 HA 和 HI 检测。本研究探讨了使用戊二醛固定tRBCs，这可能是储存于-80的可能性^º C和容易地用于HA和HI测定法。

材料和方法

研究中总共使用了九种人类和禽流感病毒亚型，即 A H1N1、H3N2、H4N6、H5N1、H6N1、H7N9、H9N2、H11N1 和 B 型。土耳其红细胞用戊二醛固定。HA 和 HI 测定由两个不同的操作员使用新鲜和戊二醛固定的 tRBC 进行了 3 次。使用“t 检验”比较固​​定和新鲜 RBC 之间 HA 和 HI 滴度差异的显着性。在 -80 ^º C 下储存三周之前和之后，对固定红细胞的性能进行了评估。

结果

使用新鲜和戊二醛固定的火鸡 RBC 的平均 HA 和 HI 滴度之间没有显着差异（p > 0.05）。此外，使用固定 tRBC 在 -80 ^º C储存之前和之后的 HA 和 HI 滴度相当，表明固定和储存 RBC 的适用性。

结论

这是使用固定和储存的 tRBC 进行流感病毒 HA 和 HI 测定的第一份报告，突出了它们作为流感实验室诊断的即用型试剂的适用性。